cp's OEIS Frontend

A210734 Primes p such that p + 1 or p - 1 is a concatenation of successive even numbers starting from 2.

%I A210734 #11 Apr 03 2023 10:36:13
%S A210734 3,23,2467,246809,246811,24681012141619,
%T A210734 24681012141618202224262830323436384041,
%U A210734 24681012141618202224262830323436384042444649
%N A210734 Primes p such that p + 1 or p - 1 is a concatenation of successive even numbers starting from 2.
%C A210734 a(9) has 625 digits, a(10) has 1476 digits, a(11) has 5048 digits, a(12) has 39024 digits.
%H A210734 Arkadiusz Wesolowski, <a href="/A210734/b210734.txt">Table of n, a(n) for n = 1..10</a>
%H A210734 G. L. Honaker, Jr. and Chris Caldwell, <a href="https://t5k.org/curios/cpage/20588.html">24681...50451 (625-digits)</a>
%H A210734 Henri & Renaud Lifchitz, <a href="http://www.primenumbers.net/prptop/searchform.php?form=%3F24681012141618202224%3F&amp;action=Search">PRP Records</a>
%t A210734 lst = {}; c = 0; Do[c = c*10^IntegerLength[n] + n; a = c - 1; If[PrimeQ[a], AppendTo[lst, a]]; b = c + 1; If[PrimeQ[b], AppendTo[lst, b]], {n, 2, 48, 2}]; lst
%Y A210734 Cf. A019520.
%K A210734 base,nonn
%O A210734 1,1
%A A210734 _Arkadiusz Wesolowski_, May 10 2012