来自在线整数百科全书的问候语!http://oeis.org/ Search: id:a061395 Showing 1-1 of 1 %I A061395 %S A061395 0,1,2,1,3,2,4,1,2,3,5,2,6,4,3,1,7,2,8,3,4,5,9,2,3,6,2,4,10,3,11,1,5, %T A061395 7,4,2,12,8,6,3,13,4,14,5,3,9,15,2,4,3,7,6,16,2,5,4,8,10,17,3,18,11,4, %U A061395 1,6,5,19,7,9,4,20,2,21,12,3,8,5,6,22,3,2,13,23,4,7,14,10,5,24,3,6,9,11,15 %N A061395 Let p be the largest prime factor of n; if p is the k-th prime then set a(n) = k; a(1) = 0 by convention. %C A061395 Records occur at the primes. -罗伯特·G·威尔逊·V.,12月30日2007。%%C A061395为N>1:第0N行长度为A067 255。6月11日,2013岁的C·A061395 A(n)=具有海因茨数n的最大的部分。我们定义了一个分区P=(pH1,Py2,…,Pyr]作为乘积的海因茨数(pJ-Th Prime,j=1…R)(AALIS P海因茨在A215366中使用的概念,作为一个分区的编码)。例如,对于分区〔1, 1, 2,4, 10〕,我们得到2×2×3×7×29=2436。例子:A(20)=3;实际上,具有海因茨数20=2×2×5的分区是[1,1,3]。-德意志,04,2015,%AH,061395,lvar Ibeas,n,a(n)n=1…100000的表(Harry J. Smith的前1000项)%%A061395素数分解中指数序列的索引条目%F A061395 A000 000(A(n))=A00 630(n);A(n)=A04904(A00 630(n))。5月22日,2003岁的F A061395 A243055(n)=A(n)-A055 39 6(n)。- _Antti Karttunen_, Mar 07 2017 %e A061395 a(20) = 3 since the largest prime factor of 20 is 5, which is the 3rd prime. %p A061395 with(numtheory): %p A061395 a:= n-> `if`(n=1, 0, pi(max(factorset(n)[]))): %p A061395 seq(a(n), n=1..100); # _Alois P. Heinz_, Aug 03 2013 %t A061395 Insert[Table[PrimePi[FactorInteger[n][[ -1]][[1]]], {n, 2, 120}], 0, 1] (* _Stefan Steinerberger_, Apr 11 2006 *) %t A061395 f[n_] := PrimePi[ FactorInteger@n][[ -1, 1]]; Array[f, 94] (* _Robert G. Wilson v_, Dec 30 2007 *) %o A061395 (PARI) { for (n=1, 1000, if (n==1, a=0, f=factor(n)~; p=f[1, length(f)]; a=primepi(p)); write("b061395.txt", n, " ", a) ) } \\ _Harry J. Smith_, Jul 22 2009 %o A061395 (Haskell) %o A061395 a061395 = a049084 . a006530 -- _Reinhard Zumkeller_, Jun 11 2013 %o A061395 (Python) %o A061395 from sympy import primepi, primefactors %o A061395 def a(n): return 0 if n==1 else primepi(primefactors(n)[-1]) %o A061395 print [a(n) for n in range(1, 101)] # _Indranil Ghosh_, May 14 2017 %Y A061395 Cf. A006530, A055396, A061394, A133674, A243055. %K A061395 easy,nice,nonn %O A061395 1,3 %A A061395 _Henry Bottomley_, Apr 30 2001 %E A061395 Definition reworded by _N. J. A. Sloane_, Jul 01 2008 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE