A307647 Numbers that are the sum of a prime number and a positive cube.
3, 4, 6, 8, 10, 11, 12, 13, 14, 15, 18, 19, 20, 21, 24, 25, 27, 29, 30, 31, 32, 34, 37, 38, 39, 40, 42, 44, 45, 46, 48, 49, 50, 51, 54, 55, 56, 58, 60, 61, 62, 64, 66, 67, 68, 69, 70, 71, 72, 74, 75, 77, 79, 80, 81, 83, 84, 86, 87, 88, 90, 91, 93, 94, 95, 97, 98, 100, 101, 102, 104, 105
Offset: 1
Keywords
Links
- Robert Israel, Table of n, a(n) for n = 1..10000
Programs
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Maple
N:= 200: # for terms <= N P:= select(isprime,[2,seq(i,i=3..N-1,2)]): C:= [seq(j^3,j=1..floor((N-2)^(1/3)))]: sort(convert(select(`<=`,{seq(seq(p+c,p=P),c=C)},N),list)); # Robert Israel, Apr 22 2019
Formula
Exponents in expansion of (Sum_{i>=1} x^prime(i)) * (Sum_{j>=1} x^(j^3)).