A124190 a(n) is the largest prime < 4*a(n-1) for n > 1, with a(1) = 2.

2, 7, 23, 89, 353, 1409, 5623, 22483, 89923, 359663, 1438643, 5754571, 23018273, 92073083, 368292317, 1473169213, 5892676849, 23570707387, 94282829533, 377131318127, 1508525272477, 6034101089897, 24136404359569, 96545617438253, 386182469752993, 1544729879011951

Offset: 1

Author

Artur Jasinski, Dec 16 2006

Keywords

• nonn

Links

• Artur Jasinski, Dec 16 2006, Table of n, a(n) for n = 1..40

Crossrefs

Cf. A126031.

Programs

Mathematica

NestList[NextPrime[4#,-1]&,2,30] (* Harvey P. Dale, Oct 11 2023 *)