cp's OEIS Frontend

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.

A088244 Number of 3-smooth divisors of n!.

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%I A088244 #13 Aug 30 2019 08:00:12
%S A088244 1,1,2,4,8,8,15,15,24,40,45,45,66,66,72,84,112,112,153,153,171,190,
%T A088244 200,200,253,253,264,336,364,364,405,405,480,512,528,528,630,630,648,
%U A088244 684,741,741,800,800,840,924,946,946,1081,1081,1104,1152,1200,1200
%N A088244 Number of 3-smooth divisors of n!.
%H A088244 Amiram Eldar, <a href="/A088244/b088244.txt">Table of n, a(n) for n = 0..10000</a>
%F A088244 a(n) = A072078(A000142(n)).
%F A088244 a(n) = a(n-1) iff gcd(n,6) = 1.
%F A088244 a(n) = (A011371(n)+1)*(A054861(n)+1).
%t A088244 a[n_] := ((1 + IntegerExponent[n!, 2])*(1 + IntegerExponent[n!, 3])); Array[a, 100, 0] (* _Amiram Eldar_, Aug 30 2019 *)
%Y A088244 Cf. A000005, A003586.
%Y A088244 Cf. A000142, A072078.
%Y A088244 Cf. A011371, A054861.
%K A088244 nonn
%O A088244 0,3
%A A088244 _Reinhard Zumkeller_, Jan 23 2004