A215649 Reversals of tribonacci numbers (sorted).

0, 0, 1, 1, 2, 4, 7, 18, 31, 42, 44, 405, 472, 729, 941, 5071, 6313, 8675, 9853, 21066, 31591, 90601, 447014, 514121, 674557, 713322, 770074, 4606468, 7359831, 7575552, 8089735, 19520951, 52494292, 69005989, 106799181, 474396516, 777547433, 2586342311, 3016782802

Offset

0,5

Comments

This is to A004170 as tribonacci numbers A000073 are to Fibonacci numbers A000045. Note that tribonacci(20) = 35890 is, upon reversal, 09853, then the leading 0 is truncated, making the 5-digit number into the 4-digit number 9853. Similarly, R(4700770) = 770074.

Links

Harvey P. Dale, Table of n, a(n) for n = 0..1000

Example

A000073(n) for n = 7, 8, 9 = 13, 24, 44, 81. Reversed, those are 31, 42, 44, 18, and sorted that is 18, 31, 42, 44.

Mathematica

Sort[FromDigits[Reverse[IntegerDigits[#]]]&/@LinearRecurrence[{1, 1, 1}, {0, 0, 1, 1}, 40]] (* Harvey P. Dale, Nov 22 2015 *)

Crossrefs

Cf. A000045, A000073, A004086, A004170, A004091, A140463, A214855, A004086.

Sequence in context: A047871 A290877 A103032 * A259351 A300913 A232484

Adjacent sequences: A215646 A215647 A215648 * A215650 A215651 A215652

Keyword

nonn,base,easy

Author

Jonathan Vos Post, Mar 09 2013

Status

approved