A292634 - OEIS

A292634

Numbers n such that 4 iterations of 'Reverse and Subtract' lead to n, whereas fewer than 4 iterations do not lead to n.

169140971830859028, 312535222687464777, 464929563535070436, 651817066348182933

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OFFSET

1,1

COMMENTS

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.

LINKS

Table of n, a(n) for n=1..4.

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

FORMULA

n = f^4(n), n <> f^k(n) for k < 4, where f: x -> |x - reverse(x)|.

EXAMPLE

|169140971830859028 - 820958038179041961| = 651817066348182933

|651817066348182933 - 339281843660718156| = 312535222687464777

|312535222687464777 - 777464786222535213| = 464929563535070436

|464929563535070436 - 634070535365929464| = 169140971830859028

CROSSREFS