A048572 a(n) = sum of digits of a(n-1)*a(n-2).

1, 2, 2, 4, 8, 5, 4, 2, 8, 7, 11, 14, 10, 5, 5, 7, 8, 11, 16, 14, 8, 4, 5, 2, 1, 2, 2, 4, 8, 5, 4, 2, 8, 7, 11, 14, 10, 5, 5, 7, 8, 11, 16, 14, 8, 4, 5, 2, 1, 2, 2, 4, 8, 5, 4, 2, 8, 7, 11, 14, 10, 5, 5, 7, 8, 11, 16, 14, 8, 4, 5, 2

Offset

1,2

Comments

This sequence is periodic with period 24. - T. D. Noe, Feb 15 2008

Links

Table of n, a(n) for n=1..72.

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-24) for n >= 25. - Wesley Ivan Hurt, Mar 09 2023

Mathematica

Nest[Append[#, Total[IntegerDigits[Last[#]#[[-2]]]]]&, {1, 2}, 80]  (* Harvey P. Dale, Apr 21 2011 *)
PadRight[{}, 100, {1, 2, 2, 4, 8, 5, 4, 2, 8, 7, 11, 14, 10, 5, 5, 7, 8, 11, 16, 14, 8, 4, 5, 2}] (* Harvey P. Dale, Jan 18 2015 *)

Crossrefs

Sequence in context: A077968 A123958 A377231 * A337561 A121173 A160159

Adjacent sequences: A048569 A048570 A048571 * A048573 A048574 A048575

Keyword

nonn,easy,nice,base

Author

David Johnson-Davies

Status

approved