三角数丰富与不足:
这样的数字s(n)是n个,大于n个被称为富足数字。如果n是一个三角形数,那么它可以被称为丰富的三角数例如,36是一个三角形数字,s(36)=1+2+3+4+6+9+12+18=55,大于36。所以36是一个丰富的三角数。
全部丰富的三角数低于105是:
36,66,78,120,210,276,300,378,528,630,666,780,820,990,1128,1176,1326,1540,1596,1770,1830,2016,2080,2346,2556,2628,2850,3160,3240,3486,3570,3828,4095,4278,4560,4656,4950,5460,5778,5886,6216,6328,6786,7140,7260,7626,7875,8256,8646,8778,9180,9730,9870,10296,10440,10878,11628,12090,12246,12720,12880,13530,14028,14196,14706,15400,15576,16110,16290,16836,17020,17766,17955,18336,18528,19110,19900,20100,20706,20910,21528,21736,21945,22578,23220,23436,24090,24310,24976,25200,25878,26106,26565,26796,27966,28680,28920,29646,29890,30628,30876,31626318783264033670339303471634980357783712837950382263906039340,40470,41328,41616,42486,43660,43956,44850,45150,46056,46360,47586,48516,48828,49770,51040,51360,52326,52650,53628,53956,54285,55278,56280,56616,57630,57970,58996,59340,60378,60726,61425,61776,62128,63546,64620,64980,66066,66430,67896,69006,69378,70500,72390,73536,73920,75078,76636,77028,78210,78606,79800,80200,81810,82215,83028,83436,84666,86320,86736,87990,88410,89676,90100,91806,93096,935289483096580902098346和98790。
这样的数字s(n)是n个,小于n个被称为缺陷数字。如果n是一个三角形数,那么它可以被称为缺三角数例如21是一个三角形数字,s(21)=1+3+7=11,小于21。所以21是一个三角数不足。
全部三角数不足低于105是:
1,3,10,15,21,45,55,91,105,136,153,171,190,231,253,325,351,406,435,465,561,595,703,741,861,903,946,1035,1081,1225,1275,1378,1431,1485,1653,1711,1891,1953,2145,2211,2278,2415,2485,2701,2775,2926,3003,3081,3321,3403,3655,3741,3916,4005,4186,4371,4465,4753,4851,5050,5151,5253,5356,5565,5671,5995,6105,6441,6555,6670,6903,7021,7381,7503,7750,8001,8385,8515,8911,9045,9316,9453,9591,10011,10153,10585,10731,11026,11175,11325,11476,11781,11935,12403,12561,13041,13203,13366,13695,13861,14365,14535,14878,15051,15225,15753,15931,16471,16653,17205,17391,17578,18145,18721,18915,19306,19503,19701,20301,20503,21115,21321,22155,22366,22791,23005,23653,23871,24531,24753,25425,25651,26335,27028,27261,27495,27730,28203,28441,29161,29403,30135,30381,31125,31375,32131,32385,32896,33153,33411,34191,34453,35245,35511,36046,36315,36585,36856,37401,37675,38503,38781,39621,39903,40186,40755,41041,41905,42195,42778,43071,43365,44253,44551,45451,45753,46665,46971,47278,47895,48205,49141,49455,50086,50403,50721,51681,52003,52975,53301,54615,54946,55611,55945,56953,57291,58311,58653596856003161075624816283563190639036426165341657036679567161,67528,68265,68635,69751,70125,70876,71253,71631,72010,72771,73153,74305,74691,75466,75855,76245,77421,77815,79003,79401,80601,81003,81406,82621,83845,84255,85078,85491,85905,87153,87571,88831,89253,90525,90951,91378,92235,92665,93961,94395952669570396141974619790399235和99681。