A286661 - OEIS

%I #12 Sep 17 2018 20:32:01

%S 3,41,43,641,643,8641,108643,18161412108641,

%T 525048464442403836343230282624222018161412108643,

%U 646260585654525048464442403836343230282624222018161412108641

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

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

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

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

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

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

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

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/ConsecutiveNumberSequences.html">Consecutive Number Sequences</a>

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

%Y Cf. A038396, A019520, A210734.

%K nonn,base

%O 1,1

%A _XU Pingya_, May 12 2017