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 A246817 #19 May 22 2025 10:21:40 %S A246817 0,5,15,30,50,100,130,165,205,250,350,405,465,530,600,750,830,915, %T A246817 1005,1100,1300,1405,1515,1630,1750,2125,2255,2390,2530,2675,2975, %U A246817 3130,3290,3455,3625,3975,4155,4340,4530,4725,5125,5330,5540,5755,5975,6425,6655 %N A246817 Possible number of trailing zeros in hyperfactorials (A002109). %C A246817 The number of trailing zeros in A002109 increases every 5 terms since the exponent of the factor 5 increases every 5 terms and the exponent of the factor 2 increases every 2 terms. %H A246817 Chai Wah Wu, <a href="/A246817/b246817.txt">Table of n, a(n) for n = 1..1000</a> %o A246817 (Python) %o A246817 from sympy import multiplicity %o A246817 A246817, p5 = [0], 0 %o A246817 for n in range(5,5*10**3,5): %o A246817 p5 += multiplicity(5,n)*n %o A246817 A246817.append(p5) # _Chai Wah Wu_, Sep 05 2014 %Y A246817 Cf. A002109, A191610, A246839. %K A246817 nonn,base %O A246817 1,2 %A A246817 _Chai Wah Wu_, Sep 03 2014