A178914 -id:A178914 - cp's OEIS frontend

A089186 Decreases from 9 * 10^k down to 1, restarting at 9 * 10^(k+1).

9, 8, 7, 6, 5, 4, 3, 2, 1, 90, 89, 88, 87, 86, 85, 84, 83, 82, 81, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28

Offset: 1

Artemario Tadeu Medeiros da Silva (artemario(AT)uol.com.br), Dec 07 2003

Points of local maxima: 9 * 10^k.

a(n) is the 10's complement of n. - Robert Israel, Jul 03 2024

Alois P. Heinz, Table of n, a(n) for n = 1..9999

Cf. A052268, A178914 (essentially the same).

[10^#Intseq(n)-n : n in [1..68]]; // Arkadiusz Wesolowski, Nov 09 2013

a:= n-> 10^length(n)-n:
seq(a(n), n=1..72);  # Alois P. Heinz, Sep 18 2024

Join[Range[9,1,-1],Range[90,1,-1]] (* Harvey P. Dale, Jun 06 2013 *)

a(n) = 10^(1+logint(n, 10)) - n \\ Ruud H.G. van Tol, Jan 16 2023

a(n) = 10^(floor(log_10(n)) + 1) - n.

A068822 a(n) = gcd(n,c(n)), where c(n) is the 10's complement of n.

Original entry on oeis.org

1, 2, 1, 2, 5, 2, 1, 2, 1, 10, 1, 4, 1, 2, 5, 4, 1, 2, 1, 20, 1, 2, 1, 4, 25, 2, 1, 4, 1, 10, 1, 4, 1, 2, 5, 4, 1, 2, 1, 20, 1, 2, 1, 4, 5, 2, 1, 4, 1, 50, 1, 4, 1, 2, 5, 4, 1, 2, 1, 20, 1, 2, 1, 4, 5, 2, 1, 4, 1, 10, 1, 4, 1, 2, 25, 4, 1, 2, 1, 20, 1, 2

Offset: 1

Amarnath Murthy, Mar 08 2002

			a(45) = 5 as 10's complement of 45 is 100-45 = 55 and (45,55) = 5.

Alois P. Heinz, Table of n, a(n) for n = 1..9999

Cf. A089186, A178914.

a:=n-> igcd((10^length(n)-n), n):
seq(a(n), n=1..100);  # Alois P. Heinz, Sep 22 2015

GCD[#, 10^(IntegerLength[#]) - #] & /@ Range[82] (* Jayanta Basu, Aug 07 2013 *)

a(n) = gcd(n,A089186(n)) = gcd(n,A178914(n)). - Alois P. Heinz, Nov 05 2018

cp's OEIS Frontend

A089186 Decreases from 9 * 10^k down to 1, restarting at 9 * 10^(k+1).

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