A110930 a(1) = 1; a(n) = nextprime(2*a(n-1)) for n > 1.

1, 3, 7, 17, 37, 79, 163, 331, 673, 1361, 2729, 5471, 10949, 21911, 43853, 87719, 175447, 350899, 701819, 1403641, 2807303, 5614657, 11229331, 22458671, 44917381, 89834777, 179669557, 359339171, 718678369, 1437356741, 2874713497

Offset

1,2

Links

G. C. Greubel, Table of n, a(n) for n = 1..1000

Formula

a(n) = A065545(n-1), n>1. - R. J. Mathar, Aug 18 2008

Example

a(6) = nextprime(2*a(5)) = nextprime(2*37) = nextprime(74) = 79.

Mathematica

<<NumberTheory`; p = 1; Print[p]; Do[p = NextPrime[2*p]; Print[p], {n, 2, 50}]
RecurrenceTable[{a[n] == NextPrime[2*a[n - 1]], a[1] == 1}, a, {n, 1, 50}] (* G. C. Greubel, Oct 19 2017 *)
NestList[NextPrime[2#]&, 1, 30] (* Harvey P. Dale, Apr 22 2023 *)

Crossrefs

Sequence in context: A393382 A244629 A065545 * A026646 A026668 A111210

Adjacent sequences: A110927 A110928 A110929 * A110931 A110932 A110933

Keyword

nonn

Author

Ryan Propper, Sep 23 2005

Status

approved