A008461 Take sum of squares of digits of previous term.

7, 49, 97, 130, 10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1

Offset

1,1

Links

Table of n, a(n) for n=1..94.

Index entries for periodic sequences.

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

Formula

a(n) = 1 for n > 5. - Charles R Greathouse IV, May 26 2026

Mathematica

NestList[Total[IntegerDigits[#]^2]&, 7, 100] (* Harvey P. Dale, Mar 12 2014 *)

Prog

(PARI) a(n)=if(n>5, 1, [7, 49, 97, 130, 10][n]) \\ Charles R Greathouse IV, May 26 2026

Crossrefs

Sequence in context: A230655 A357302 A343771 * A043131 A082701 A044145

Adjacent sequences: A008458 A008459 A008460 * A008462 A008463 A008464

Keyword

nonn,base,easy

Author

N. J. A. Sloane

Status

approved