A158790 Odd integers n such that (x^n + 1/x^n)/sqrt(8) + 1 is prime, where x = sqrt(8) + sqrt(7).

1, 3, 11, 13, 77, 83, 181, 381, 525, 3829, 4141, 6093, 9589

Offset

1,2

Comments

No other terms below 32000.

Links

Table of n, a(n) for n=1..13.

David Broadhurst, The House That Jack Built

David Broadhurst and others, The house that Jack built, digest of 69 messages in primenumbers Yahoo group, Mar 22 - May 10, 2009.

Prog

(PARI) { y = Mod(x, x^4-30*x^2+1); q8 = Mod(-1/2*x^3 + 31/2*x, x^4-30*x^2+1); forstep(n=1, 10^4, 2, if( ispseudoprime( polcoeff(lift((y^n+y^(-n))/q8), 0) + 1 ), print(n); ); ); } \\ Max Alekseyev, Dec 09 2011

Crossrefs

Sequence in context: A370488 A105290 A201426 * A176049 A228237 A186078

Adjacent sequences: A158787 A158788 A158789 * A158791 A158792 A158793

Keyword

more,nonn

Author

Cino Hilliard, Mar 26 2009

Extensions

a(11)-a(13) from Max Alekseyev, Dec 09 2011

Status

approved