A184899 n such that the n-th centered 12-gonal number is prime. Indices of prime star numbers.

2, 3, 4, 6, 8, 9, 10, 11, 13, 14, 19, 20, 21, 23, 24, 31, 32, 33, 34, 36, 37, 39, 42, 43, 44, 46, 47, 48, 52, 56, 59, 61, 66, 68, 74, 75, 78, 79, 85, 87, 89, 94, 96, 98, 101, 102, 105, 107, 108, 110, 113, 118, 121, 124, 125, 127, 130, 131, 133, 135, 136, 138

Offset

1,1

Comments

For n > 3, A003154(a(n)) = A057199(2*a(n)-2). - Chai Wah Wu, Sep 17 2019

Links

Zak Seidov, Table of n, a(n) for n = 1..1000

Formula

{n: 6*n^2 - 6*n + 1 is prime} = {n: A003154(n) is in A000040}.

Example

98 is in the sequence because 6*98^2 - 6*98 + 1 = 57037 is prime.

Mathematica

Select[Range[140], PrimeQ[6#^2-6#+1]&]  (* Harvey P. Dale, Feb 16 2011 *)

Crossrefs

Cf. A083577, A000040, A003154, A057199.

Sequence in context: A075449 A342559 A005458 * A039034 A047302 A121217

Adjacent sequences: A184896 A184897 A184898 * A184900 A184901 A184902

Keyword

nonn,easy

Author

Jonathan Vos Post, Feb 01 2011

Status

approved