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

1,1

Links

Table of n, a(n) for n=1..45.

Formula

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

Example

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

Mathematica

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

Prog

(PARI) vector(80, n, prime(n+n^2)) \\ Michel Marcus, Feb 12 2015
(Magma) [NthPrime(n+n^2): n in [1..50]]; // Vincenzo Librandi, Feb 24 2015

Crossrefs

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

Sequence in context: A153009 A147168 A147183 * A098547 A256316 A194486

Adjacent sequences: A254952 A254953 A254954 * A254956 A254957 A254958

Keyword

nonn

Author

Waldemar Puszkarz, Feb 11 2015

Status

approved