A181956 Smallest prime greater than n*(n+1)^2/2.

2, 3, 11, 29, 53, 97, 149, 227, 331, 457, 607, 797, 1019, 1277, 1579, 1931, 2333, 2767, 3251, 3803, 4421, 5087, 5821, 6637, 7507, 8461, 9479, 10589, 11777, 13063, 14419, 15877, 17431, 19079, 20849, 22691, 24659, 26717, 28901, 31219, 33623, 36187, 38833, 41627

Offset

0,1

Links

Charles R Greathouse IV, Table of n, a(n) for n = 0..10000

Formula

a(n) ~ n^3 / 2. - Charles R Greathouse IV, Aug 03 2012

Example

a(1)=2 because prime 2 > (0*(0+1)^2/2) = 0, a(2)=3 because prime 3 > (1*(1+1)^2/2) = 2, a(3)=11 because prime 11 > (2*(2+1)^2/2) = 9.

Mathematica

Table[NextPrime[n*(n+1)^2/2], {n, 0, 50}] (* T. D. Noe, Apr 03 2012 *)

Prog

(PARI) a(n)=nextprime(n*(n+1)^2/2+1) \\ Charles R Greathouse IV, Aug 03 2012

Crossrefs

Cf. A006002, A097050.

Sequence in context: A235474 A075641 A176316 * A237038 A309755 A309701

Adjacent sequences: A181953 A181954 A181955 * A181957 A181958 A181959

Keyword

nonn

Author

Gerasimov Sergey, Apr 03 2012

Status

approved