OFFSET
1,1
COMMENTS
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..5000
FORMULA
This is the sorted, made unique set {binomial(k+1,2) + binomial(L+1,2), 1 <= k <= L sufficiently large}, excluding members from A000217 (triangular numbers).
EXAMPLE
a(6) = 12 = 6 + 6,
a(17) = 31 = 3 + 28 = 10 + 21.
MATHEMATICA
(* First run the program for A051533 *) Complement[%, tri] (* Alonso del Arte, Feb 15 2011 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Feb 14 2011
STATUS
approved