A163632 Triple and reverse digits.

1, 3, 9, 72, 612, 6381, 34191, 375201, 3065211, 3365919, 75779001, 300733722, 661102209, 7266033891, 37610189712, 631965038211, 3364115985981, 34975974329001, 300789229729401, 302881986763209, 726982069546809

Offset: 1

Author

Dmitry Kamenetsky, Aug 02 2009

Keywords

• nonn
• base

Links

• Vaclav Kotesovec, Table of n, a(n) for n = 1..1000
• Vaclav Kotesovec, Plot of a(n)^(1/n) for n = 1..10000

Crossrefs

The following are parallel families: A000079 (2^n), A004094 (2^n reversed), A028909 (2^n sorted up), A028910 (2^n sorted down), A036447 (double and reverse), A057615 (double and sort up), A263451 (double and sort down); A000244 (3^n), A004167 (3^n reversed), A321540 (3^n sorted up), A321539 (3^n sorted down), A163632 (triple and reverse), A321542 (triple and sort up), A321541 (triple and sort down).

Cf. A132064, A045539, A132078, A132114, A132113, A133361.

Programs

Mathematica

a[n_] := a[n] = If[n==1, 1, IntegerReverse[3a[n-1]]];
Array[a, 40] (* Jean-François Alcover, Jan 01 2021 *)

Extensions

Offset changed from 0 to 1 by Vaclav Kotesovec, Jan 03 2020