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 A071523 #17 Apr 29 2025 04:44:17
%S A071523 1,2,3,4,5,6,7,8,9,10,11,12,12,13,14,15,15,16,16,17,18,19,19,20,21,21,
%T A071523 22,23,23,24,24,25,26,26,27,28,28,28,28,29,29,30,30,31,32,32,32,33,34,
%U A071523 35,35,35,35,36,37,38,38,38,38,39,39,39,40,41,41,42,42,42,42,43,43,44
%N A071523 Number of 11-smooth numbers <= n.
%C A071523 An 11-smooth number is a number of the form 2^x*3^y*5^z*7^u*11^v (x,y,z,u,v) >= 0.
%H A071523 Amiram Eldar, <a href="/A071523/b071523.txt">Table of n, a(n) for n = 1..10000</a>
%F A071523 a(n) = Card{ k | A051038(k) <= n }.
%t A071523 Accumulate[Table[If[Max[FactorInteger[n][[;;,1]]]<=11,1,0],{n,120}]] (* _Harvey P. Dale_, Sep 02 2024 *)
%o A071523 (PARI) a(n)=sum(k=1,n,(k<4) || 13>vecmax(factor(k)~[1,]))
%Y A071523 Cf. A051038.
%Y A071523 Number of p-smooth numbers <= n: A070939 (p=2), A071521 (p=3), A071520 (p=5), A071604 (p=7), this sequence (p=11), A080684 (p=13), A080685 (p=17), A080686 (p=19).
%K A071523 easy,nonn
%O A071523 1,2
%A A071523 _Benoit Cloitre_, Jun 02 2002