A037464 Bisection of A076605.

3, 5, 7, 7, 11, 13, 13, 17, 19, 19, 23, 23, 5, 29, 31, 31, 11, 37, 37, 41, 43, 43, 47, 47, 17, 53, 53, 19, 59, 61, 61, 13, 67, 67, 71, 73, 73, 11, 79, 79, 83, 83, 29, 89, 89, 31, 31, 97, 97, 101, 103, 103, 107, 109, 109, 113, 113, 23, 17, 17, 41, 41, 127, 127, 131, 131, 19

Offset: 1

Author

N. J. A. Sloane, Nov 29 2002

Keywords

• nonn
• easy

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A076605, A074399.

Programs

Mathematica

Table[ Last[ Table[ # [[1]]] & /@ FactorInteger[n^2 - 1]], {n, 2, 150, 2}]

PARI

a(n) = my(p = factor(4*n^2-1)[, 1]); p[#p]; \\ Amiram Eldar, Nov 03 2024

Formula

a(n) = max(A006530(2n-1), A006530(2n+1)).

a(n) = A076605(2*n). - Amiram Eldar, Nov 03 2024

Extensions

Extended by Robert G. Wilson v, Dec 02 2002