A053837 - OEIS

A053837

Sum of digits of n modulo 10.

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

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OFFSET

0,3

LINKS

Table of n, a(n) for n=0..104.

FORMULA

a(n) =A010879(A007953(n)) =(n+a(floor[n/10])) mod 10. So can construct sequence by starting with 0 and mapping 0->0123456789, 1->1234567890, 2->2345678901 etc. (e.g. 0, 0123456789, 0123456789123456789023456789013456789012456..., etc.) and looking at n-th digit of a term with sufficient digits.

EXAMPLE

a(59)=4 because 5+9 = 14 = 4 mod 10

MATHEMATICA

Table[Mod[Total[IntegerDigits[n]], 10], {n, 0, 120}] (* Harvey P. Dale, Oct 02 2018 *)

PROG

(PARI) a(n)=sumdigits(n)%10 \\ Charles R Greathouse IV, Feb 02 2023

CROSSREFS

Cf. A000120, A007953, A010060, A053838-A053844.

Sequence in context: A037265 A292685 A285093 * A128244 A010888 A177274

Adjacent sequences: A053834 A053835 A053836 * A053838 A053839 A053840

KEYWORD

base,nonn,easy

AUTHOR

Henry Bottomley, Mar 28 2000

STATUS

approved