A214517 Differences between the numbers n such that 4n^2 + 1 is prime.

1, 1, 2, 2, 1, 2, 2, 1, 5, 2, 7, 1, 5, 4, 5, 3, 2, 8, 3, 2, 2, 1, 2, 2, 6, 2, 3, 2, 5, 3, 2, 2, 10, 1, 2, 7, 3, 3, 2, 5, 3, 2, 2, 3, 5, 2, 8, 3, 4, 6, 7, 5, 17, 1, 5, 2, 3, 7, 5, 3, 2, 2, 10, 1, 2, 2, 8, 3, 20, 4, 6, 7, 3, 4, 5, 20, 1, 4, 1, 4, 10, 3, 3, 2, 3

Offset: 1

Author

T. D. Noe, Aug 06 2012

Keywords

• nonn

Comments

Sequence A001912 has the values of n. This sequence is the first differences of A001912.

Links

• T. D. Noe, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A121326 (primes of the form 1+4*n^2), A001912 (values of n).

Programs

Mathematica

Differences[Select[Range[100], PrimeQ[1 + 4*#^2] &, 101]]

Formula

a(n) = A214516(n)/2 for n > 1.