This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A338651 #29 Jan 08 2024 01:37:57 %S A338651 0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,2,1,2,1,2,1,2,1,3,1,2,2,2,1,3,1,3,2,2, %T A338651 1,4,1,2,2,4,1,3,1,3,3,2,1,5,1,3,2,3,1,4,2,4,2,2,1,6,1,2,3,4,2,4,1,3, %U A338651 2,4,1,7,1,2,3,3,2,4,1,6,3,2,1,6,2,2,2,5,1,7,2,3,2,2,2,7,1,3,4,5,1,4,1,5,4,2,1,7,1,5 %N A338651 Number of divisors of n which are greater than 7. %H A338651 Seiichi Manyama, <a href="/A338651/b338651.txt">Table of n, a(n) for n = 1..10000</a> %H A338651 <a href="/index/Di#divisors">Index entries for sequences related to divisors of numbers</a>. %F A338651 G.f.: Sum_{k>=1} x^(8*k) / (1 - x^k). %F A338651 L.g.f.: -log( Product_{k>=8} (1 - x^k)^(1/k) ). %F A338651 G.f.: Sum_{k>=8} x^k/(1 - x^k). - _Seiichi Manyama_, Jan 07 2023 %F A338651 Sum_{k=1..n} a(k) ~ n * (log(n) + 2*gamma - 503/140), where gamma is Euler's constant (A001620). - _Amiram Eldar_, Jan 08 2024 %t A338651 Table[DivisorSum[n, 1 &, # > 7 &], {n, 1, 110}] %t A338651 nmax = 110; CoefficientList[Series[Sum[x^(8 k)/(1 - x^k), {k, 1, nmax}], {x, 0, nmax}], x] // Drop[#, 1] & %t A338651 nmax = 110; CoefficientList[Series[-Log[Product[(1 - x^k)^(1/k), {k, 8, nmax}]], {x, 0, nmax}], x] Range[0, nmax] // Drop[#, 1] & %o A338651 (PARI) a(n) = sumdiv(n, d, d>7); \\ _Michel Marcus_, Apr 22 2021 %o A338651 (PARI) my(N=100, x='x+O('x^N)); concat([0, 0, 0, 0, 0, 0, 0], Vec(sum(k=8, N, x^k/(1-x^k)))) \\ _Seiichi Manyama_, Jan 07 2023 %Y A338651 Column k=8 of A135539. %Y A338651 Cf. A000005, A001620, A023645, A032741, A321014, A338648, A338649, A338650, A338652, A338653. %K A338651 nonn,easy %O A338651 1,16 %A A338651 _Ilya Gutkovskiy_, Apr 22 2021 %E A338651 a(1)-a(7) prepended by _David A. Corneth_, Jun 13 2022