A190197 a(1) = 2. For n > 1, a(n) is the least prime > a(n-1)*n/2.

2, 3, 5, 11, 29, 89, 313, 1259, 5669, 28349, 155921, 935531, 6080957, 42566731, 319250501, 2554004029, 21709034261, 195381308371, 1856122429537, 18561224295377, 194892855101467, 2143821406116139, 24653946170335607, 295847354044027363, 3698091925550342059, 48075195032154446803

Offset

1,1

Links

Table of n, a(n) for n=1..26.

Mathematica

nxt[{n_, a_}]:={n+1, NextPrime[a (n+1)/2]}; NestList[nxt, {1, 2}, 30][[All, 2]] (* Harvey P. Dale, Feb 05 2020 *)

Prog

(PARI) lista(nn) = {my(a=2); print1(a, ", "); for (n=2, nn, if (a*n % 2, a = nextprime(a*n/2), a = nextprime(a*n/2+1)); print1(a, ", "); ); } \\ Michel Marcus, Sep 15 2019

Crossrefs

Sequence in context: A090235 A265418 A346052 * A173631 A182987 A334814

Adjacent sequences: A190194 A190195 A190196 * A190198 A190199 A190200

Keyword

nonn

Author

Pierre CAMI, May 08 2011

Extensions

More terms from Michel Marcus, Sep 15 2019

Name edited by Felix Fröhlich, Sep 15 2019

Status

approved