来自在线整数百科全书的问候语!http://oeis.org/ Search: id:a287483 Showing 1-1 of 1 %I A287483 %S A287483 1,2,3,5,6,10,14,15,21,22,26,30,42,66,70,78,102,105,110,114,130,138, %T A287483 154,165,170,174,182,186,190,195,210,330,390,462,510,546,570,690,714, %U A287483 770,798,858,870,910,930,966,1110,1122,1155,1190,1218,1230,1254,1290 %N A287483 Irregular triangle T(n,k) read by rows: row n lists numbers m with A002110(n) <= m < A002110(n+1) such that omega(m) = n. %C A287483 The primorial A002110(n) is the smallest squarefree number with n prime factors. 在这里,第n行的三角形是一个无平方数的列表,其N个素因子大于并且包括a00 2110(n),但小于a00 2110(n+1)。n,a(n)n=0…10309的表(行0<n<=9).%%A28,Eric Weisstein数学世界,原始的Eric Weisstein数学世界,无平方的%E A28 783.序列从1开始,因为它等于A00 2110(0)并且具有0个素因子。The first primes less than 6 come next, followed by the first squarefree semiprimes (A006881) less than 30 and the smallest terms of A033992 less than 210, etc. %e A287483 Triangle begins: %e A287483 n Row n %e A287483 0: 1; %e A287483 1: 2, 3, 5; %e A287483 2: 6, 10, 14, 15, 21, 22, 26; %e A287483 3: 30, 42, 66, 70, 78, 102, 105, 110, 114, 130, ..., 195; %e A287483 ... %e A287483 In each row n, the squarefree terms m must have omega(m) = n. %t A287483 Table[Select[Range[#, Prime[n + 1] # - 1] &@ Product[Prime@ i, {i, n}], And[SquareFreeQ@ #, PrimeOmega@ # == n] &], {n, 0, 4}] // Flatten %Y A287483 Cf. A001221, A002110, A005117, A006881, A033992, A287484, A287691. %K A287483 nonn,easy,tabf %O A287483 0,2 %A A287483 _Michael De Vlieger_, May 25 2017 %E A287483 Edited by _N. J. A. Sloane_, Jun 05 2017 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE