OFFSET
1,1
COMMENTS
If the triangular number 0 is allowed, only one additional prime occurs: 3. In that case, the sequence becomes A117112.
A subsequence of A051533. - Wolfdieter Lang, Jan 11 2017
LINKS
T. D. Noe, Table of n, a(n) for n = 1..10000
EXAMPLE
2 = 1 + 1
7 = 1 + 6
11 = 1 + 10
13 = 10 + 3, etc.
MATHEMATICA
tri = Table[n (n + 1)/2, {n, 40}]; Select[Union[Flatten[Outer[Plus, tri, tri]]], # <= tri[[-1]]+1 && PrimeQ[#] &] (* T. D. Noe, Apr 07 2011 *)
PROG
(PARI) is(n)=for(k=sqrtint(4*n+1)\2+1, (sqrtint(8*n+1)-1)\2, if(ispolygonal(n-k*(k+1)/2, 3), return(n>3 && isprime(n)))); n==2 \\ Charles R Greathouse IV, Nov 07 2014
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Andrew S. Plewe, Apr 15 2006
STATUS
approved