OFFSET
1,1
PROG
(PARI) maxt(n) = {k = 1; while ((t=k*(k+1)/2) < n, k++); if (t == n, t, k--; k*(k+1)/2); }
lista(nn) = {forprime(p = 2, nn, if (! ispolygonal(p - maxt(p), 3) && ispolygonal(2*p - maxt(2*p), 3), print1(p, ", "); ); ); } \\ Michel Marcus, Jul 25 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Shevelev, Sep 30 2008
EXTENSIONS
More terms from Michel Marcus, Jul 25 2014
STATUS
approved