A280637 Sum of the digits of n^2+1.

1, 2, 5, 1, 8, 8, 10, 5, 11, 10, 2, 5, 10, 8, 17, 10, 14, 11, 10, 11, 5, 10, 17, 8, 19, 14, 20, 10, 20, 14, 10, 17, 8, 10, 14, 11, 19, 11, 14, 10, 8, 17, 19, 14, 20, 10, 11, 5, 10, 8, 8, 10, 14, 11, 19, 11, 14, 10, 17, 17, 10, 14, 20, 19, 20, 14, 19, 17, 17, 19, 14

Offset

0,2

Comments

For all k, iterations k->a(k) will reach the {5, 8, 11} cycle. See the Mathematical Reflections.

Links

Table of n, a(n) for n=0..70.

Mathematical Reflections, Solution to Problem S294, Issue 2, 2014, p. 12.

Formula

a(n) = A007953(A002522(n)).

Prog

(PARI) a(n) = sumdigits(n^2+1)

Crossrefs

Cf. A002522, A007953.

Sequence in context: A259449 A174815 A021401 * A271872 A286677 A199868

Adjacent sequences: A280634 A280635 A280636 * A280638 A280639 A280640

Keyword

nonn,base

Author

Michel Marcus, Jan 07 2017

Status

approved