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 A279496 #14 Feb 16 2025 08:33:38
%S A279496 1,1,1,1,2,1,1,1,1,2,1,1,1,2,2,1,1,1,1,2,1,1,1,1,2,1,1,2,1,3,1,1,1,1,
%T A279496 2,1,1,1,1,2,1,2,1,1,2,1,1,1,1,2,1,1,1,1,3,2,1,1,1,3,1,1,1,1,2,1,1,1,
%U A279496 1,3,1,1,1,1,2,1,1,1,1,2,1,1,1,2,2,1,1,1,1,3,2,1,1,1,2,1,1,2,1,2,1,1,1,1,2,1,1,1,1,3,1,2,1,1,2,1,1,1,1,3
%N A279496 Number of square pyramidal numbers dividing n.
%H A279496 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SquarePyramidalNumber.html">Square Pyramidal Number</a>.
%H A279496 <a href="/index/Ps#pyramidal_numbers">Index to sequences related to pyramidal numbers</a>.
%F A279496 G.f.: Sum_{k>=1} x^(k*(k+1)*(2*k+1)/6)/(1 - x^(k*(k+1)*(2*k+1)/6)).
%F A279496 Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = 18 - 24*log(2) = 1.364467... . - _Amiram Eldar_, Jan 02 2024
%e A279496 a(10) = 2 because 10 has 4 divisors {1,2,5,10} among which 2 divisors {1,5} are square pyramidal numbers.
%t A279496 Rest[CoefficientList[Series[Sum[x^(k (k + 1) (2 k + 1)/6)/(1 - x^(k (k + 1) (2 k + 1)/6)), {k, 120}], {x, 0, 120}], x]]
%Y A279496 Cf. A000330, A046951.
%K A279496 nonn,easy
%O A279496 1,5
%A A279496 _Ilya Gutkovskiy_, Dec 13 2016