A387786 - OEIS

%I #63 Mar 15 2026 13:36:13

%S 2,1,3,4,7,11,81,29,11,4,51,55,601,656,7521,7718,93251,969001,2522601,

%T 2061943,4454854,7976156,1013421,7759898,9133778,67639861,93637767,

%U 826772161,829904029,916766561,950766471,2303357681,2514214523,4022757184,7071796356,4535549011,76354370611

%N a(0)=2, a(1)=1, and thereafter a(n) = R(a(n-1) + a(n-2)) where R(x) = A004086(x) is the decimal digit reversal of x.

%H Paolo Xausa, <a href="/A387786/b387786.txt">Table of n, a(n) for n = 0..1000</a>

%p R:= n-> (s-> parse(cat(s[-i]$i=1..length(s))))(""||n):

%p a:= proc(n) option remember; `if`(n<2, 2-n, R(a(n-1)+a(n-2)) ) end:

%p seq(a(n), n=0..36);  # _Alois P. Heinz_, Feb 08 2026

%t Module[{a, n}, RecurrenceTable[{a[n] == IntegerReverse[a[n-1] + a[n-2]], a[0] == 2, a[1] == 1}, a, {n, 0, 40}]] (* _Paolo Xausa_, Feb 17 2026 *)

%o (PARI) lista(nn) = my(x=2, y=1); print1(x, ", "); print1(y, ", "); for (n=1, nn, my(z=fromdigits(Vecrev(digits(x+y)))); print1(z, ", "); x = y; y = z;); \\ _Michel Marcus_, Feb 08 2026

%Y Cf. A000032, A004086, A014258, A036447.

%K nonn,base

%O 0,1

%A _Aminos Abijad_, Feb 06 2026