A167482 a(n)=n-1 if n is prime, otherwise a(n)=n+1.

2, 1, 2, 5, 4, 7, 6, 9, 10, 11, 10, 13, 12, 15, 16, 17, 16, 19, 18, 21, 22, 23, 22, 25, 26, 27, 28, 29, 28, 31, 30, 33, 34, 35, 36, 37, 36, 39, 40, 41, 40, 43, 42, 45, 46, 47, 46, 49, 50, 51, 52, 53, 52, 55, 56, 57, 58, 59, 58, 61, 60, 63, 64, 65, 66, 67, 66, 69, 70, 71, 70, 73

Offset

1,1

Links

Table of n, a(n) for n=1..72.

Mathematica

Table[If[PrimeQ[n], n-1, n+1], {n, 1, 200}]

Crossrefs

Cf. A068519, A167480, A175027.

Sequence in context: A084600 A216760 A318724 * A328601 A137327 A143913

Adjacent sequences: A167479 A167480 A167481 * A167483 A167484 A167485

Keyword

nonn

Author

Zak Seidov, Nov 04 2009

Status

approved