A065881 - OEIS

A065881

Ultimate modulo 10: right-hand nonzero digit of n.

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

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

OFFSET

1,2

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..1000

Index entries for sequences related to final digits of numbers

FORMULA

If n mod 10 = 0 then a(n) = a(n/10), otherwise a(n) = n mod 10.

EXAMPLE

a(3)=3, a(23)=3, a(30)=3, a(12300)=3.

MATHEMATICA

um10[n_]:=Module[{idns=Split[IntegerDigits[n]]}, If[idns[[-1, 1]] == 0, idns[[-2, 1]], idns[[-1, 1]]]]; Array[um10, 110] (* Harvey P. Dale, Dec 26 2016 *)

PROG

(PARI) { for (n=1, 1000, a=n; while (a%10 == 0, a\=10); write("b065881.txt", n, " ", a%10) ) } \\ Harry J. Smith, Nov 03 2009

(Python)

def A065881(n): return int(str(n).rstrip('0')[-1]) # Chai Wah Wu, Dec 07 2023

CROSSREFS

In base 2 this is A000012, base 3 A060236 and base 4 A065882. For n <= 100 this sequence is also "Remove final zeros from n" which in bases 2, 3 and 4 produces A000265, A038502 and A065883. Cf. A010879.

Sequence in context: A257295 A004427 A113230 * A133048 A214950 A373064

Adjacent sequences: A065878 A065879 A065880 * A065882 A065883 A065884

KEYWORD

base,nonn

AUTHOR

Henry Bottomley, Nov 26 2001

STATUS

approved