

A051698


Closest prime to n that is different from n (break ties by taking the smaller prime).


3



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

0,1


LINKS

Harvey P. Dale, Table of n, a(n) for n = 0..1000


EXAMPLE

Closest primes to 0,1,2,3,4 are 2,2,3,2,3.


MATHEMATICA

cp[n_]:=Module[{p1=NextPrime[n, 1], p2=NextPrime[n]}, If[p2n<np1, p2, p1]]; Join[{2}, Table[cp[k], {k, 80}]] (* Harvey P. Dale, Dec 11 2018 *)


CROSSREFS

Related sequences: A023186A023188, A046929A046931, A051650, A051652, A051697A051702, A051728A051730.
Sequence in context: A048475 A204597 A285734 * A046773 A175402 A281726
Adjacent sequences: A051695 A051696 A051697 * A051699 A051700 A051701


KEYWORD

nonn,easy


AUTHOR

N. J. A. Sloane


EXTENSIONS

More terms from James A. Sellers


STATUS

approved



