A112667 a(n+1) is the sum of the units digit of a(n) and the square of the tens digit of a(n).

97, 88, 72, 51, 26, 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, 1, 1, 1, 1, 1, 1, 1

Offset

1,1

Links

Table of n, a(n) for n=1..102.

K. Sengup, What is the next number in the series 97 88 72 51 26?.

Index entries for periodic sequences, period 1.

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

Formula

a(n) = 1 for n > 6. - Charles R Greathouse IV, Jun 03 2026

Mathematica

nxt[n_]:=Module[{u=Last[IntegerDigits[n]], t=Floor[n/10]}, u+t^2]; NestList[nxt, 97, 110] (* Harvey P. Dale, Oct 22 2013 *)

Prog

(PARI) a(n)=if(n>6, 1, [97, 88, 72, 51, 26, 10][n]) \\ Charles R Greathouse IV, Jun 03 2026

Crossrefs

Sequence in context: A244192 A075478 A126146 * A106419 A253387 A074482

Adjacent sequences: A112664 A112665 A112666 * A112668 A112669 A112670

Keyword

nonn,base,easy

Author

N. J. A. Sloane, based on email from R. J. Mathar, Apr 04 2007

Status

approved