A292846 Numbers n such that 11 iterations of 'Reverse and Subtract' lead to n, whereas fewer than 11 iterations do not lead to n.

166425621223026859056339052269787863565428, 192910929628537040766341860254183960991698, 307567270506730945853551459962385036145286, 311906350108036145286307567270199935391877

Offset

1,1

Comments

There are 11 forty-two-digit terms in the sequence. Further terms are obtained (a) by inserting at the center of these terms either any number of 0's (for 166425621223026859056339052269787863565428, 311906350108036145286307567270199935391877, 466287189883036620417374974360601118217236, 658139747564935391877311906350534262959233, 703288139752915027377325180481642968027593) or any number of 9's (for the other six terms) and (b) by concatenating a term any number of times with itself and inserting an equal number of 0's at all junctures. Method (b) may be applied recursively to all terms. - Clarified by Ray Chandler, Oct 14 2017.

Links

Ray Chandler, Table of n, a(n) for n = 1..11

J. H. E. Cohn, Palindromic differences, Fibonacci Quart. 28 (1990), no. 2, 113-120.

Formula

n = f^11(n), n <> f^k(n) for k < 11, where f: x -> |x - reverse(x)|.

Example

166425621223026859056339052269787863565428 -> 658139747564935391877311906350534262959233 -> 325180485129881782763533712811068515027377 -> 448540030730236434571833574377853069054146 -> 192910929628537040766341860254183960991698 -> 703288139752915027377325180481642968027593 -> 307567270506730945853551459962385036145286 -> 374974360076539008301807089075220036620417 -> 339052269946031972406296711860450026859056 -> 311906350108036145286307567270199935391877 -> 466287189883036620417374974360601118217236 -> 166425621223026859056339052269787863565428.

Crossrefs

Cf. A072142, A072143, A072718, A072719, A215669, A292634, A292635, A292856, A292857, A292858, A292859.

Sequence in context: A120335 A095476 A292856 * A181789 A095478 A291353

Adjacent sequences: A292843 A292844 A292845 * A292847 A292848 A292849

Keyword

nonn,base

Author

Meritxell Vila Miñana, Sep 24 2017

Extensions

Terms corrected by Ray Chandler, Sep 27 2017

Status

approved