A081600 Let n = 10x + y where 0 <= y <= 9, x >= 0. Then a(n) = 9x+y.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 108, 109, 110

Offset: 0

Author

N. J. A. Sloane, Apr 22 2003

Keywords

• nonn
• easy

Comments

More than the usual number of terms are displayed in order to distinguish this from some closely related sequences. - N. J. A. Sloane, Mar 22 2014

Links

• Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,0,0,0,0,0,1,-1).

Crossrefs

Cf. A081502. Different from A028904.

Programs

Magma

k:=9; [n-(10-k)*Floor(n/10): n in [0..150]]; // Bruno Berselli, Jun 24 2014

Maple

f1:=proc(n) local x,y;
y:= (n mod 10);
x:=(n-y)/10;
9*x+y;
end;
[seq(f1(n),n=0..200)];

PARI

my(n, x, y); vector(500, n, y=(n-1)%10; x=(n-1-y)\10; 9*x+y) \\ Colin Barker, Jun 23 2014

PARI

a(n)=n - n\10 \\ Charles R Greathouse IV, Sep 01 2015

Formula

G.f.: x*(x^2 +x +1)*(x^6 +x^3 +1) / ((x -1)^2*(x +1)*(x^4 -x^3 +x^2 -x +1)*(x^4 +x^3 +x^2 +x +1)). - Colin Barker, Jun 24 2014

a(n) = n - floor(n/10). - Bruno Berselli, Jun 24 2014