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 A166645 #18 Feb 06 2025 08:22:39
%S A166645 1,15,20,225,30,300,40,3375,400,450,60,4500,70,600,600,50625,90,6000,
%T A166645 100,6750,800,900,120,67500,900,1050,8000,9000,150,9000,160,759375,
%U A166645 1200,1350,1200,90000,190,1500,1400,101250,210,12000,220,13500,12000,1800
%N A166645 Totally multiplicative sequence with a(p) = 5*(p+1) for prime p.
%H A166645 G. C. Greubel, <a href="/A166645/b166645.txt">Table of n, a(n) for n = 1..10000</a>
%F A166645 Multiplicative with a(p^e) = (5*(p+1))^e. If n = Product p(k)^e(k) then a(n) = Product (5*(p(k)+1))^e(k).
%F A166645 a(n) = A165826(n) * A003959(n) = 5^bigomega(n) * A003959(n) = 5^A001222(n) * A003959(n).
%t A166645 a[1] = 1; a[n_] := (fi = FactorInteger[n]; Times @@ ((fi[[All, 1]] + 1)^fi[[All, 2]])); Table[a[n]*5^(PrimeOmega[n]), {n, 1, 100}] (* _G. C. Greubel_, May 20 2016 *)
%t A166645 f[p_, e_] := (5*(p+1))^e; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* _Amiram Eldar_, Oct 17 2023 *)
%o A166645 (PARI) a(n) = {my(f = factor(n)); for (k=1, #f~, f[k,1] = 5*(f[k,1]+1)); factorback(f);} \\ _Michel Marcus_, May 21 2016
%Y A166645 Cf. A001222, A003959, A165826.
%K A166645 nonn,easy,mult
%O A166645 1,2
%A A166645 _Jaroslav Krizek_, Oct 18 2009