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 A180365 #35 Oct 23 2023 17:41:28 %S A180365 1,53,1471,29425,496623,7518850,106030594,1421760251,18362473634, %T A180365 230375375227,2824280446479,33978264556380,402439152166882, %U A180365 4703975577244852,54365786164534232,622220063695532731,7060841638683030355,79525016215415440837 %N A180365 Partial sums up to 10^n of A007425. %H A180365 Henri Lifchitz, <a href="/A180365/b180365.txt">Table of n, a(n) for n = 0..23</a> (first 21 terms from Hiroaki Yamanouchi) %F A180365 a(n) = A061201(10^n). %o A180365 (PARI) a(n)=sum(k=1, 10^n, numdiv(k)*floor((10^n)/k)); %o A180365 vector(7, n, a(n-1)) \\ _Altug Alkan_, Sep 24 2015 %o A180365 (Python) %o A180365 from math import isqrt %o A180365 from sympy import integer_nthroot %o A180365 def A180365(n): return (m:=integer_nthroot(t:=10**n,3)[0])**3+3*sum(-(s:=isqrt(r:=t//i))**2+(sum(r//k for k in range(1,s+1))<<1)-sum(t//(i*j) for j in range(1,m+1)) for i in range(1,m+1)) # _Chai Wah Wu_, Oct 23 2023 %Y A180365 Cf. A007425, A061201. %K A180365 nonn %O A180365 0,2 %A A180365 _Andrew Lelechenko_, Jan 19 2011 %E A180365 One more term (a(16)) and typo in crossrefs fixed by _Andrew Lelechenko_, Apr 13 2011 %E A180365 a(17) from _Hiroaki Yamanouchi_, Jul 15 2014