cp's OEIS Frontend

A323051 Numbers that cannot be written as a sum of two or fewer 11-smooth numbers (A051038).

%I A323051 #21 Feb 14 2019 12:34:48
%S A323051 479,958,1151,1319,1437,1559,1679,1916,2302,2351,2395,2638,2874,2999,
%T A323051 3013,3071,3118,3353,3358,3453,3671,3737,3769,3832,3911,3957,4199,
%U A323051 4309,4311,4604,4677,4702,4703,4751,4790,4919,5037,5057,5269,5276,5389,5443,5519,5597,5683
%N A323051 Numbers that cannot be written as a sum of two or fewer 11-smooth numbers (A051038).
%C A323051 Similar to A323046 (3-smooth), A323049 (5-smooth) or A323050 (7-smooth).
%C A323051 This sequence is a subsequence of A323046, A323049, and A323050.
%C A323051 Notice that A045535(4) = a(1) = 479.
%t A323051 f[n_] := Union@Flatten@Table[2^a*3^b*5^c*7^d, {a, 0, Log2[n]}, {b, 0, Log[3, n/2^a]}, {c, 0, Log[5, n/(2^a*3^b)]}, {d, 0, Log[7, n/(2^a*3^b*5^c)]}];
%t A323051 b = Block[{nn = 3000, s}, s = f[nn]; {0, 1}~Join~
%t A323051     Select[Union@Flatten@Outer[Plus, s, s], # <= nn &]];
%t A323051 Complement[Range[3000], b]
%Y A323051 See A323046 (3-smooth), A323049 (5-smooth) or A323050 (7-smooth). Cf. A051038, A045535 (or A062241).
%K A323051 nonn
%O A323051 1,1
%A A323051 _Carlos Alves_, Jan 03 2019