A237575 Fibonacci-like numbers with nonincreasing positive digits. Let a** denote the number that is obtained from a if its digits are written in nonincreasing order. Let a<+>b = (a + b)**. a(0)=0, a(1)=1, for n>=2, a(n) = a(n-1) <+> a(n-2).

0, 1, 1, 2, 3, 5, 8, 31, 93, 421, 541, 962, 5310, 7622, 93221, 843100, 963321, 8642110, 9654310, 98642210, 986522100, 8654311100, 9864332000, 88654311100, 98865431100, 987754221100, 9866652211000, 86544432110000, 98644321110000, 888755322110000

Offset: 0

Author

Vladimir Shevelev, Feb 09 2014

Keywords

• nonn
• base

Links

• Peter J. C. Moses, Table of n, a(n) for n = 0..499

Crossrefs

Cf. A000045, A001129, A004185, A069638, A237568.

Programs

Maple

a:= proc(n) option remember; `if`(n<2, n, parse(cat(
      sort(convert(a(n-1)+a(n-2), base, 10), `>`)[])))
    end:
seq(a(n), n=0..30);  # Alois P. Heinz, Aug 31 2022

Mathematica

a[0]:=0;a[1]:=1;a[n_]:=a[n]=FromDigits[Reverse[Sort[IntegerDigits[a[n-1]+a[n-2]]]]];Map[a,Range[0,20]] (* Peter J. C. Moses, Feb 09 2014 *)

Extensions

Correction and extension by Peter J. C. Moses