A171407 a(n) = (2^(2^(1+2*n)) + 3) / 7.

37, 613566757, 48611766702991209066196372490252601637, 1915401132848942442796289285457978018211337974370341911103365920531680575724792425257410614023843346812861694026640864407679126115992367135204807000869157

Offset

1,1

Links

Table of n, a(n) for n=1..4.

Mathematica

(2^(2^(1 + 2*Range[4])) + 3)/7 (* Paolo Xausa, Feb 23 2026 *)

Prog

(PARI) a(k)=(2^2^(1 + 2*k) + 3)/7

Crossrefs

Sequence in context: A238840 A345467 A329226 * A023930 A022072 A351221

Adjacent sequences: A171404 A171405 A171406 * A171408 A171409 A171410

Keyword

nonn,less

Author

A.K. Devaraj, Dec 08 2009

Extensions

Revised by Sean A. Irvine, Feb 22 2026

Status

approved