A074966 - OEIS

A074966

a(n) = least k such that n^n + k is prime.

1, 1, 2, 1, 12, 7, 4, 43, 10, 19, 62, 35, 16, 27, 28, 13, 74, 107, 18, 91, 32, 87, 14, 95, 96, 43, 68, 135, 120, 19, 58, 7, 58, 63, 54, 31, 42, 115, 10, 157, 110, 13, 4, 403, 122, 457, 534, 37, 18, 31, 226, 253, 20, 193, 102, 177, 392, 45, 194, 257, 102, 79, 454, 231, 306

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OFFSET

1,3

COMMENTS

"Are there any n except 1, 2 and 4 that make n^n + 1 a prime? He [Sierpiński] has shown that if such a prime exists it is greater than 10^30000." - Ogilvy and Anderson

REFERENCES

C. Stanley Ogilvy and John T. Anderson, Excursions in Number Theory. Dover. New York: 1988. Page 82.

LINKS

Hans Havermann and Seiichi Manyama, Table of n, a(n) for n = 1..2500 (Seiichi Manyama to 500)

MATHEMATICA

Array[Block[{k = 1}, While[! PrimeQ[k + #], k++]; k] &[#^#] &, 65] (* Michael De Vlieger, Jul 06 2018 *)

PROG

(PARI) a(n)=(x->nextprime(x)-x)(n^n) \\ Charles R Greathouse IV, Nov 25 2014

CROSSREFS

Cf. A055385, A074967.

Sequence in context: A372508 A257635 A085752 * A128413 A058843 A343861

Adjacent sequences: A074963 A074964 A074965 * A074967 A074968 A074969

KEYWORD

nonn

AUTHOR

Zak Seidov, Oct 03 2002

EXTENSIONS

More terms from Robert G. Wilson v, Oct 04 2002

Name taken from Comments section by Jon E. Schoenfield, Jan 14 2015

STATUS

approved