A074860 a(n) = a(n-1) + R(a(n-2)) + R(a(n-3)) where a(0)=a(1)=a(2)=1 and R(k) = A004086(k) is the reverse of k.

1, 1, 1, 3, 5, 9, 17, 31, 111, 195, 319, 1021, 2525, 4639, 11092, 25708, 64083, 173846, 292644, 979061, 2073724, 2680995, 7115676, 17380240, 30136219, 41109707, 136581181, 298634398, 550610143, 1625232666, 2859685613, 9863026929, 19691221772, 32153295043

Offset: 0

Author

Felice Russo, Sep 11 2002

Keywords

• easy
• base
• nonn

Crossrefs

Cf. A000213, A004086.

Programs

Maple

R:= n-> (s-> parse(cat(s[-i]$i=1..length(s))))(""||n):
a:= proc(n) option remember; `if`(n<3, 1,
      a(n-1) + R(a(n-2)) + R(a(n-3)))
    end:
seq(a(n), n=0..33);  # Alois P. Heinz, Jun 17 2021

Extensions

Corrected and extended by David Garber, Oct 23 2002

Offset corrected by and more terms from Alois P. Heinz, Jun 17 2021