A377231 a(n) = digital root of 2^Fibonacci(n).

1, 2, 2, 4, 8, 5, 4, 2, 8, 7, 2, 5, 1, 5, 5, 7, 8, 2, 7, 5, 8, 4, 5, 2, 1, 2, 2, 4, 8, 5, 4, 2, 8, 7, 2, 5, 1, 5, 5, 7, 8, 2, 7, 5, 8, 4, 5, 2, 1, 2, 2, 4, 8, 5, 4, 2, 8, 7, 2, 5, 1, 5, 5, 7, 8, 2, 7, 5, 8, 4, 5, 2, 1, 2, 2, 4, 8, 5, 4, 2, 8, 7, 2, 5, 1, 5, 5, 7, 8, 2, 7, 5, 8, 4, 5, 2

Offset

0,2

Comments

This sequence has period 24.

Links

Table of n, a(n) for n=0..95.

Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1).

Formula

a(n) = (a(n-1) * a(n-2) - 1) mod 9 + 1.

a(n) = A010888(A000301(n)).

Mathematica

Module[{a, n}, RecurrenceTable[{a[n] == Mod[a[n-1]*a[n-2] - 1, 9] + 1, a[0] == 1, a[1] == 2}, a, {n, 0, 99}]] (* or *)
PadRight[{}, 100, {1, 2, 2, 4, 8, 5, 4, 2, 8, 7, 2, 5, 1, 5, 5, 7, 8, 2, 7, 5, 8, 4, 5, 2}] (* Paolo Xausa, Nov 08 2024 *)

Crossrefs

Cf. A000301, A010888.

Sequence in context: A077964 A077968 A123958 * A048572 A337561 A121173

Adjacent sequences: A377227 A377229 A377230 * A377232 A377233 A377234

Keyword

nonn,easy,base

Author

Robert Bruce Gray, Oct 20 2024

Status

approved