A264979 - OEIS

A264979

Bijective base-9 reverse: a(0) = 0; for n >= 1, a(n) = A030108(n/A264981(n)) * A264981(n).

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 19, 28, 37, 46, 55, 64, 73, 18, 11, 20, 29, 38, 47, 56, 65, 74, 27, 12, 21, 30, 39, 48, 57, 66, 75, 36, 13, 22, 31, 40, 49, 58, 67, 76, 45, 14, 23, 32, 41, 50, 59, 68, 77, 54, 15, 24, 33, 42, 51, 60, 69, 78, 63, 16, 25, 34, 43, 52, 61, 70, 79, 72, 17, 26, 35, 44, 53, 62, 71, 80, 81

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OFFSET

0,3

COMMENTS

Self-inverse permutation of nonnegative integers.

It appears that a(m x) == 0 (mod m) for m = 2^k and m = 5*2^k, k >= 0, but not for other m. Is there a simple explanation? - M. F. Hasler, May 21 2021

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..6561

Index entries for sequences that are permutations of the natural numbers

FORMULA

a(0) = 0; for n >= 1, a(n) = A030108(n/A264981(n)) * A264981(n).

PROG

(Scheme)

(define (A264979 n) (if (zero? n) n (* (A030108 (/ n (A264981 n))) (A264981 n))))

(PARI) apply( {A264979(n)=A030108(n/n=9^valuation(n+!n, 9))*n}, [0..99]) \\ M. F. Hasler, May 21 2021

CROSSREFS

Cf. A030108, A264981.

Cf. A265338 (a(8n)/8).