This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A292634 #25 Jan 05 2025 19:51:41 %S A292634 169140971830859028,312535222687464777,464929563535070436, %T A292634 651817066348182933 %N A292634 Numbers n such that 4 iterations of 'Reverse and Subtract' lead to n, whereas fewer than 4 iterations do not lead to n. %C A292634 There are 4 eighteen-digit terms in the sequence. Terms of derived sequences can be obtained either by inserting at the center of their digits any number of 9's or by concatenating a term any number of times with itself and inserting an equal number of 0's at all junctures. %H A292634 J. H. E. Cohn, <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Scanned/28-2/cohn.pdf">Palindromic differences</a>, Fibonacci Quart. 28 (1990), no. 2, 113-120. %F A292634 n = f^4(n), n <> f^k(n) for k < 4, where f: x -> |x - reverse(x)|. %e A292634 |169140971830859028 - 820958038179041961| = 651817066348182933 %e A292634 |651817066348182933 - 339281843660718156| = 312535222687464777 %e A292634 |312535222687464777 - 777464786222535213| = 464929563535070436 %e A292634 |464929563535070436 - 634070535365929464| = 169140971830859028 %Y A292634 Cf. A072142, A072143, A072718, A072719, A215669, A292635, A292846, A292856, A292857, A292858, A292859. %K A292634 nonn,base,more %O A292634 1,1 %A A292634 _Meritxell Vila Miñana_, Sep 20 2017 %E A292634 Terms ordered by _Ray Chandler_, Sep 27 2017