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 A359244 #16 Aug 16 2023 02:27:13 %S A359244 0,1,0,1,1,1,0,2,0,1,1,2,0,2,0,1,1,1,1,3,0,1,1,1,0,3,0,2,1,1,0,3,1,1, %T A359244 1,2,0,2,0,2,1,1,0,4,1,1,2,1,0,2,0,2,1,2,0,3,0,2,1,2,1,3,0,1,1,1,0,5, %U A359244 0,1,2,1,0,2,1,2,1,1,1,4,0,2,1,3,0,2,0,1,2,1 %N A359244 Number of divisors of 5*n-4 of form 5*k+2. %C A359244 Also number of divisors of 5*n-4 of form 5*k+3. %H A359244 Seiichi Manyama, <a href="/A359244/b359244.txt">Table of n, a(n) for n = 1..10000</a> %F A359244 a(n) = A001877(5*n-4) = A001878(5*n-4). %F A359244 G.f.: Sum_{k>0} x^(2*k)/(1 - x^(5*k-2)). %F A359244 G.f.: Sum_{k>0} x^(3*k-1)/(1 - x^(5*k-3)). %t A359244 a[n_] := DivisorSum[5*n-4, 1 &, Mod[#, 5] == 2 &]; Array[a, 100] (* _Amiram Eldar_, Aug 16 2023 *) %o A359244 (PARI) a(n) = sumdiv(5*n-4, d, d%5==2); %o A359244 (PARI) a(n) = sumdiv(5*n-4, d, d%5==3); %o A359244 (PARI) my(N=100, x='x+O('x^N)); concat(0, Vec(sum(k=1, N, x^(2*k)/(1-x^(5*k-2))))) %o A359244 (PARI) my(N=100, x='x+O('x^N)); concat(0, Vec(sum(k=1, N, x^(3*k-1)/(1-x^(5*k-3))))) %Y A359244 Cf. A001877, A001878. %K A359244 nonn,easy %O A359244 1,8 %A A359244 _Seiichi Manyama_, Dec 22 2022