A320516 - OEIS

%I #129 Nov 10 2018 08:52:30

%S 7774777,777767777,77777677777,99999199999,1111118111111,

%T 7777774777777,111111181111111,333333373333333,77777777677777777,

%U 99999999299999999,9999999992999999999,33333333333733333333333,77777777777677777777777,333333333333373333333333333

%N Palindromic wing primes that are also Lychrel candidates.

%C Lychrel candidates are natural numbers that seem unable to form a palindrome through the iterative process of repeatedly reversing its digits and adding the resulting numbers.

%C On January 23, 2017 a Russian schoolboy, Andrey S. Shchebetov, announced on his web site that he had found a sequence of the first 126 numbers (125 of them never reported before) that take exactly 261 steps to reach a 119-digit palindrome. That sequence was published in the OEIS as A281506. The trajectory of the last number of that sequence, 1186061987030929990, under the "Reverse and Add!" operation was published separately in the OEIS as A281507.

%H Robert Liguori, <a href="https://bit.ly/2yIY6Mu">Github project SequencePier</a>

%Y Cf. A077798, A000040, A023108, A281506, A281507.

%K nonn,base

%O 1,1

%A _Robert James Liguori_, Oct 29 2018

%E Seven terms inserted by _Jon E. Schoenfield_, Oct 31 2018

%E a(14) from _Jon E. Schoenfield_, Nov 01 2018