A118136 a(n) = 2 + (2*n! mod n+1).

2, 2, 3, 2, 5, 2, 7, 2, 2, 2, 11, 2, 13, 2, 2, 2, 17, 2, 19, 2, 2, 2, 23, 2, 2, 2, 2, 2, 29, 2, 31, 2, 2, 2, 2, 2, 37, 2, 2, 2, 41, 2, 43, 2, 2, 2, 47, 2, 2, 2, 2, 2, 53, 2, 2, 2, 2, 2, 59, 2, 61, 2, 2, 2, 2, 2, 67, 2, 2, 2, 71, 2, 73, 2, 2, 2, 2, 2, 79, 2, 2, 2, 83, 2, 2, 2, 2, 2, 89, 2, 2, 2, 2, 2, 2, 2

Offset

0,1

Comments

Prime generating formula based on Wilson's theorem.

References

Wladyslaw Narkiewicz, The development of prime number theory: from Euclid to Hardy and Littlewood, Springer-Verlag, New York, 2000, pp. 46-47.

Links

Table of n, a(n) for n=0..95.

M. Prunescu and L. Sauras-Altuzarra, An arithmetic term for the factorial function, Examples and Counterexamples, Vol. 5 (2024).

Maple

f:=n->(2*n! mod (n+1))+2; [seq(f(n), n=0..100)];

Mathematica

a[n_] := 2 + Mod[2*n!, n + 1]
Table[a[n], {n, 0, 100}]

Crossrefs

Cf. A000040, A000142.

Sequence in context: A298422 A304716 A237984 * A356552 A258567 A076396

Adjacent sequences: A118133 A118134 A118135 * A118137 A118138 A118139

Keyword

nonn

Author

Roger L. Bagula, May 13 2006

Extensions

Edited by N. J. A. Sloane, Jun 12 2007

Status

approved