A065545 a(n) is smallest prime > 2*a(n-1), a(1) = 3.

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

Author

Robert G. Wilson v, Nov 28 2001

Keywords

• nonn

Comments

There is no common term with A055496? - Zak Seidov, Feb 04 2016

Correct, there is no common term with A055496. - Flávio V. Fernandes, Apr 10 2021

Links

• Zak Seidov, Table of n, a(n) for n = 1..102

Crossrefs

Cf. A055496.

Programs

Mathematica

NextPrim[n_Integer] := Block[ {k = n + 1}, While[ !PrimeQ[k], k++ ]; Return[k]]; a[1] = 3; a[n_] := NextPrim[ 2*a[n - 1]]; Table[ a[n], {n, 1, 20} ]
NestList[NextPrime[2*#] &, 3, 29] (* Zak Seidov, Feb 04 2016 *)

PARI

lista(nn) = {print1(a = 3, ", "); for (n=1, nn, a = nextprime(2*a+1); print1(a, ", "););} \\ Michel Marcus, Feb 04 2016