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

Author

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

Keywords

• nonn
• base

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

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

Crossrefs

Cf. A169931 - A169935.

Programs

Magma

[n - n mod 10 + 2*n mod 10: n in [0..70]]; // Vincenzo Librandi, Mar 26 2015

PARI

A169933(n)=n-n%10+(n*2)%10 \\ M. F. Hasler, Mar 25 2015

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)