A167788 Triangular numbers which are sums of three consecutive primes.

10, 15, 1891, 3403, 10153, 13861, 20503, 27261, 56953, 77815, 87571, 89253, 99681, 121771, 144991, 218791, 224785, 354061, 392941, 606651, 693253, 761995, 765703, 802011, 874503, 1017451, 1038961, 1091503, 1269621, 1348903, 1428895, 1468041

Offset

1,1

Comments

Intersection of A000217 (Triangular numbers) and A034961 (Sums of three consecutive primes).

Links

Chai Wah Wu, Table of n, a(n) for n = 1..10000 (n = 1..1390 from Donovan Johnson)

Formula

a(n) = A000217(A226145(n)). - Michel Marcus, Feb 12 2018

Mathematica

Select[Table[Prime[n]+Prime[n+1]+Prime[n+2], {n, 8!}], IntegerQ[Sqrt[1+8# ]]&] (* Vladimir Joseph Stephan Orlovsky, Feb 18 2010 *)

Prog

(Magma) [ t: n in [1..40000] | IsSquare(8*t+1) where t is &+[NthPrime(n+s): s in [0, 1, 2]] ]; // Bruno Berselli, Apr 28 2011

Crossrefs

Cf. A000217, A034961.

Cf. A226145 (corresponding indices), A226148 (the smallest of the 3 consecutive primes).

Sequence in context: A134515 A232608 A175335 * A341012 A072968 A072138

Adjacent sequences: A167785 A167786 A167787 * A167789 A167790 A167791

Keyword

nonn

Author

Zak Seidov, Nov 12 2009

Status

approved