OFFSET
1,1
EXAMPLE
PROG
(PARI) A136118vect(n, i=-1)=vector(n, k, until(0, for(j=2, #n=sum2sqr((i+=6)^2+1), n[j]%6==[5, 5]||next; n=n[j]; break(2))); n[1]\6+1) /* This uses sum2sqr(), cf. A133388. Below some simpler but much slower code. */
my(P=A000326(n)=n*(3*n-1)/2, isPent(t)=P(sqrtint(t*2\3)+1)==t); for(i=1, 299, for(j=1, (i+1)\sqrt(2), isPent(P(i)-P(j))&print1(j", ")||next(2)))
CROSSREFS
KEYWORD
nonn
AUTHOR
M. F. Hasler, Dec 25 2007
STATUS
approved