A286661 Primes of form A038396(n) - 1 or A038396(n) + 1.

3, 41, 43, 641, 643, 8641, 108643, 18161412108641, 525048464442403836343230282624222018161412108643, 646260585654525048464442403836343230282624222018161412108641

Offset

1,1

Comments

a(11) = A038396(42) + 1 = 84...43, a(12) = A038396(54) + 1 = 108...43;

a(13) = A038396(185) + 1 = 370...43, a(14) = A038396(199) - 1 = 398...41;

a(15) = A038396(224) + 1 = 448...43, a(16) = A038396(248) - 1 = 496...41;

a(17) = A038396(346) - 1 = 692...41, a(18) = A038396(947) - 1 = 1894...41.

a(19) (if it exists) will be more than A038396(3000).

a(2) and a(3) are a pair of twin primes, a(4) and a(5) also.

Links

Table of n, a(n) for n=1..10.

Eric Weisstein's World of Mathematics, Consecutive Number Sequences

Mathematica

Select[#, PrimeQ] &@ Flatten@ Table[{# - 1, # + 1} &@ FromDigits@ Flatten@ Reverse@ Take[#, n], {n, Length@ #}] &@ Array[IntegerDigits[2 #] &, 40] (* Michael De Vlieger, May 14 2017 *)

Crossrefs

Cf. A038396, A019520, A210734.

Sequence in context: A327356 A295612 A350545 * A171058 A105906 A157009

Adjacent sequences: A286658 A286659 A286660 * A286662 A286663 A286664

Keyword

nonn,base

Author

XU Pingya, May 12 2017

Status

approved