A254955 Prime numbers indexed by oblong numbers.

3, 13, 37, 71, 113, 181, 263, 359, 463, 601, 743, 911, 1091, 1291, 1511, 1747, 2017, 2297, 2617, 2903, 3271, 3617, 4003, 4409, 4831, 5297, 5743, 6247, 6761, 7297, 7853, 8443, 9029, 9631, 10271, 10973, 11717, 12413, 13109, 13879, 14717, 15461, 16301, 17191, 18059

Offset: 1

Author

Waldemar Puszkarz, Feb 11 2015

Keywords

• nonn

Examples

			a(1) = prime(1 + 1^2) = prime(2) = 3.
a(2) = prime(2 + 2^2) = prime(6) = 13.
		

Crossrefs

Cf. A000040, A002378 (n*(n+1)), A011756 (prime(n(n+1)/2)), A011757 (prime(n^2)).

Programs

Magma

[NthPrime(n+n^2): n in [1..50]]; // Vincenzo Librandi, Feb 24 2015

Mathematica

Table[Prime[n + n^2], {n, 100}] (* Puszkarz *)
Prime[2Accumulate[Range[40]]] (* Alonso del Arte, Feb 11 2015 *)

PARI

vector(80, n, prime(n+n^2)) \\ Michel Marcus, Feb 12 2015

Formula

a(n) = prime(n + n^2) = A000040(A002378(n)).