A099551 - OEIS

A099551

Odd part of n modulo 10. Final digit of A000265(n).

1, 1, 3, 1, 5, 3, 7, 1, 9, 5, 1, 3, 3, 7, 5, 1, 7, 9, 9, 5, 1, 1, 3, 3, 5, 3, 7, 7, 9, 5, 1, 1, 3, 7, 5, 9, 7, 9, 9, 5, 1, 1, 3, 1, 5, 3, 7, 3, 9, 5, 1, 3, 3, 7, 5, 7, 7, 9, 9, 5, 1, 1, 3, 1, 5, 3, 7, 7, 9, 5, 1, 9, 3, 7, 5, 9, 7, 9, 9, 5, 1, 1, 3, 1, 5, 3, 7, 1, 9, 5, 1, 3, 3, 7, 5, 3, 7, 9, 9, 5, 1, 1

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A010879(A000265(n)).

G.f. g(x) satisfies: g(x) = g(x^2) + (x + 3*x^3 + 5*x^5 + 7*x^7 + 9*x^9)/(1-x^10). - Robert Israel, Aug 10 2018

Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = 5. - Amiram Eldar, Aug 29 2024

MAPLE

f:= n -> n/2^padic:-ordp(n, 2) mod 10:

map(f, [$1..200]); # Robert Israel, Aug 10 2018