OFFSET
1,1
COMMENTS
The terms of this sequence are based on the terms of A326414 and are used to extend 288-step delayed palindromes up to 289-step delayed palindromes with the help of brute force extension of the method of undetermined coefficients.
LINKS
Anton Stefanov, Table of n, a(n) for n = 1..20
Jason Doucette and Anton Stefanov, Final 289 steps World Record proof with some numeric generators of delayed palindromes inside
Anton Stefanov, Extending the method of undetermined coefficients
Anton Stefanov, isExtends test realisation on C# (to verify A340397 elements)
EXAMPLE
The 285-step delayed palindrome 105956506309091459564960 can be extended to the 286-step delayed palindrome 53528258705040674282425, which in turn can be extended to the 287-step delayed palindrome 31769674352025337585712. This 287-step solution is unextendable so we start a new branch from the 286-step solution 53528258709000674282425 which also extends the first term of our sequence, and so on.
PROG
(C#) See Anton Stefanov link.
CROSSREFS
A326414 contains two numeric generators of delayed palindromes from our sequence: 16232852231012114813251 and 16232892231012110813251.
A072216 contains delayed palindromes of n digits with the greatest number of steps to converge.
A065199 contains records for the number of 'Reverse and Add' steps needed to reach a palindrome.
KEYWORD
nonn,base,fini
AUTHOR
Anton Stefanov, Jan 06 2021
STATUS
approved