A102124 Iccanobirt numbers (14 of 15): a(n) = R(R(a(n-1)) + R(a(n-2)) + a(n-3)), where R is the digit reversal function A004086.

0, 0, 1, 1, 2, 4, 7, 31, 42, 44, 99, 581, 823, 216, 1251, 6592, 3964, 98, 47311, 72451, 99862, 73698, 789881, 684873, 171146, 8359081, 2855313, 6626115, 92901661, 80528542, 25591874, 127303561, 518156392, 14745484, 711014964, 521206301

Offset

0,5

Comments

Digit reversal variation of tribonacci numbers A000073.

Inspired by Iccanobif numbers: A001129, A014258-A014260.

Links

Alois P. Heinz, Table of n, a(n) for n = 0..1000

Formula

a(n) = A004086(A102116(n)).

Maple

R:= n-> (s-> parse(cat(s[-i]$i=1..length(s))))(""||n):
a:= proc(n) option remember; `if`(n<3, binomial(n, 2),
       R(R(a(n-1)) + R(a(n-2)) + a(n-3)) )
    end:
seq(a(n), n=0..50);  # Alois P. Heinz, Jun 18 2014

Mathematica

R[n_]:=FromDigits[Reverse[IntegerDigits[n]]]; Clear[a]; a[0]=0; a[1]=0; a[2]=1; a [n_]:=a[n]=R[R[a[n-1]]+R[a[n-2]]+a[n-3]]; Table[a[n], {n, 0, 40}]

Crossrefs

Cf. A102111-A102125.

Sequence in context: A102122 A102123 A102125 * A280713 A233868 A295125

Adjacent sequences: A102121 A102122 A102123 * A102125 A102126 A102127

Keyword

nonn,base,easy

Author

Jonathan Vos Post and Ray Chandler, Dec 30 2004

Status

approved