A169933 a(n) = 2+n in the arithmetic defined in A169918.

0, 2, 4, 6, 8, 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78

Offset

0,2

Comments

Equivalently, apply to the last (decimal) digit of n the operation d->((d*2) mod 10), i.e., multiply the last digit by 2 and take this modulo 10; keep all other digits the same. - M. F. Hasler, Mar 25 2015

Links

Table of n, a(n) for n=0..74.

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

Formula

For n > 9, a(n) = a(n-10) + 10. For n < 10, a(n) = (2*n mod 10). - M. F. Hasler, Mar 25 2015

From Chai Wah Wu, Feb 02 2023: (Start)

a(n) = a(n-1) + a(n-10) - a(n-11) for n > 10.

G.f.: 2*x*(x^9 + x^8 + x^7 + x^6 + x^5 - 4*x^4 + x^3 + x^2 + x + 1)/(x^11 - x^10 - x + 1). (End)

Prog

(PARI) A169933(n)=n-n%10+(n*2)%10 \\ M. F. Hasler, Mar 25 2015
(Magma) [n - n mod 10 + 2*n mod 10: n in [0..70]]; // Vincenzo Librandi, Mar 26 2015

Crossrefs

Cf. A169931 - A169935.

Sequence in context: A135033 A317647 A243590 * A113603 A004520 A169918

Adjacent sequences: A169930 A169931 A169932 * A169934 A169935 A169936

Keyword

nonn,base

Author

David Applegate, Marc LeBrun and N. J. A. Sloane, Jul 20 2010

Status

approved