A105853 a(n) = sigma(n) (mod 10), i.e., unit's digit of sigma(n).

1, 3, 4, 7, 6, 2, 8, 5, 3, 8, 2, 8, 4, 4, 4, 1, 8, 9, 0, 2, 2, 6, 4, 0, 1, 2, 0, 6, 0, 2, 2, 3, 8, 4, 8, 1, 8, 0, 6, 0, 2, 6, 4, 4, 8, 2, 8, 4, 7, 3, 2, 8, 4, 0, 2, 0, 0, 0, 0, 8, 2, 6, 4, 7, 4, 4, 8, 6, 6, 4, 2, 5, 4, 4, 4, 0, 6, 8, 0, 6, 1, 6, 4, 4, 8, 2, 0, 0, 0, 4, 2, 8, 8, 4, 0, 2, 8, 1, 6, 7, 2, 6, 4, 0, 2

Offset

1,2

Links

Antti Karttunen, Table of n, a(n) for n = 1..20000

Formula

a(n) = A010879(A000203(n)). - Michel Marcus, Jul 26 2017

Maple

A105853:=n->(numtheory)[sigma](n) mod 10: seq(A105853(n), n=1..180); # Wesley Ivan Hurt, Nov 07 2017

Mathematica

Mod[DivisorSigma[1, Range[110]], 10] (* Harvey P. Dale, May 20 2019 *)

Prog

(PARI) a(n)=sigma(n)%10

Crossrefs

Cf. A000203, A010879.

Sequences sigma(n) mod k: A053866 (k=2), A074941 (k=3), A105824 (k=4), A105825 (k=5), A084301 (k=6), A105826 (k=7), A105827 (k=8), A105852 (k=9), A105853 (k=10).

Sequence in context: A077650 A244669 A316570 * A277216 A323394 A348977

Adjacent sequences: A105850 A105851 A105852 * A105854 A105855 A105856

Keyword

easy,nonn,base

Author

Shyam Sunder Gupta, May 05 2005

Status

approved