A275030 a(1) = 2. a(n) is the smallest prime such that a(n) - a(n-1) is a triangular number.

2, 3, 13, 19, 29, 107, 113, 149, 227, 233, 239, 317, 353, 359, 479, 557, 563, 569, 647, 653, 659, 1187, 1193, 1229, 1307, 1373, 1409, 1487, 1493, 1499, 1619, 1697, 1733, 1811, 1847, 1913, 1949, 2027, 2063, 2069, 2447, 2657, 2663, 2699, 2777, 2843, 2879, 2957, 2963

Offset

1,1

Links

Table of n, a(n) for n=1..49.

Mathematica

triQ[n_]:=IntegerQ[Sqrt[8n+1]];
NestList[(x=NextPrime[#]; While[!triQ[x-#], x=NextPrime[x]]; x)&, 2, 100]

Prog

(PARI) lista(nn) = {print1(p = 2, ", "); for (n=2, nn, q = nextprime(p+1); while (! ispolygonal(q-p, 3), q = nextprime(q+1)); print1(q, ", "); p = q; ); } \\ Michel Marcus, Nov 13 2016

Crossrefs

Cf. A278139.

Sequence in context: A143871 A225517 A254462 * A194598 A080359 A193507

Adjacent sequences: A275027 A275028 A275029 * A275031 A275032 A275033

Keyword

easy,nonn

Author

Ivan N. Ianakiev, Nov 13 2016

Status

approved