A320516 Palindromic wing primes that are also Lychrel candidates.

7774777, 777767777, 77777677777, 99999199999, 1111118111111, 7777774777777, 111111181111111, 333333373333333, 77777777677777777, 99999999299999999, 9999999992999999999, 33333333333733333333333, 77777777777677777777777, 333333333333373333333333333

Offset

1,1

Comments

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.

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.

Links

Table of n, a(n) for n=1..14.

Robert Liguori, Github project SequencePier

Crossrefs

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

Sequence in context: A258954 A273101 A124416 * A319809 A347424 A214194

Adjacent sequences: A320513 A320514 A320515 * A320517 A320518 A320519

Keyword

nonn,base

Author

Robert James Liguori, Oct 29 2018

Extensions

Seven terms inserted by Jon E. Schoenfield, Oct 31 2018

a(14) from Jon E. Schoenfield, Nov 01 2018

Status

approved