A129540 Triangular numbers T such that T+10 is the next prime after T.

1711, 1891, 4851, 9591, 18721, 23653, 24753, 27261, 32131, 35511, 57291, 64261, 69751, 77421, 79401, 81003, 102831, 106491, 108811, 114003, 115921, 147153, 153181, 155403, 171991, 178503, 181503, 191271, 200661, 208981, 219453

Offset: 1

Author

Zak Seidov, May 29 2007

Keywords

• nonn

Crossrefs

Cf. A000217, A129755.

Programs

Maple

a := proc (n) if nextprime((1/2)*n*(n+1)) = 10+(1/2)*n*(n+1) then (1/2)*n*(n+1) else end if end proc: seq(a(n), n = 1 .. 700); # Emeric Deutsch, Jun 20 2007

Mathematica

Select[Accumulate[Range[0, 700]],NextPrime[#]==#+10&] (* James C. McMahon, Jan 22 2025 *)

Extensions

More terms from Emeric Deutsch, Jun 20 2007