

A033558


a(n) = 2n  {smallest prime > n}.


1



0, 1, 1, 3, 3, 5, 3, 5, 7, 9, 9, 11, 9, 11, 13, 15, 15, 17, 15, 17, 19, 21, 17, 19, 21, 23, 25, 27, 27, 29, 25, 27, 29, 31, 33, 35, 33, 35, 37, 39, 39, 41, 39, 41, 43, 45, 41, 43, 45, 47, 49, 51, 47, 49, 51, 53, 55, 57
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OFFSET

1,4


COMMENTS

By Bertrand's postulate, for n>3 a(n)>2.  Zak Seidov, Mar 06 2015


LINKS

Zak Seidov, Table of n, a(n) for n = 1..1000
Wikipedia, Bertrand's postulate


MAPLE

f := n>2*nnextprime(n); [ seq(f(i), i=1..60) ];


MATHEMATICA

Table[2*nNextPrime[n], {n, 60}] (* Harvey P. Dale, Jul 23 2018 *)


PROG

(PARI) vector(60, n, 2*n  nextprime(n + 1)) \\ Zak Seidov, Mar 06 2015


CROSSREFS

Cf. A151800 (least prime > n).
Sequence in context: A078587 A335074 A239931 * A046217 A057662 A015971
Adjacent sequences: A033555 A033556 A033557 * A033559 A033560 A033561


KEYWORD

nonn


AUTHOR

N. J. A. Sloane.


STATUS

approved



