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
Crossrefs
Cf. A278139.
Programs
-
Mathematica
triQ[n_]:=IntegerQ[Sqrt[8n+1]]; NestList[(x=NextPrime[#]; While[!triQ[x-#],x=NextPrime[x]];x)&,2,100]
-
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