OFFSET
0,1
COMMENTS
For n>0, a(n) <= 6*n-2 because triangular(n) + triangular(7*n-2) = (5*n-1)^2.
PROG
(PARI) triangular(n) = n*(n+1)/2;
s=[]; for(n=0, 100, k=2; while(!issquare(triangular(n)+triangular(n+k)), k++); s=concat(s, k)); s \\ Colin Barker, Mar 31 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Alex Ratushnyak, Mar 30 2014
STATUS
approved