A169931 a(n) = 2*n in the arithmetic defined in A169918.

2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 32, 33, 34, 35, 36, 37, 38, 39, 30, 31, 42, 43, 44, 45, 46, 47, 48, 49, 40, 41, 52, 53, 54, 55, 56, 57, 58, 59, 50, 51, 62, 63, 64, 65, 66, 67, 68, 69, 60, 61, 72, 73, 74, 75, 76, 77, 78, 79, 70, 71, 82, 83, 84, 85, 86, 87, 88, 89, 80, 81, 92, 93, 94, 95, 96

Offset: 0

Author

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

Keywords

• nonn
• base

Comments

Equivalently, increase each (decimal) digit by 2 and take each result modulo 10. I.e., apply d -> (d+2 mod 10) to each digit of n. - M. F. Hasler, Mar 25 2015

Crossrefs

Cf. A048379, A169918.

Programs

Mathematica

Table[FromDigits[Mod[IntegerDigits[n]+2,10]],{n,0,100}] (* Harvey P. Dale, Aug 17 2021 *)

PARI

A169931(n)=2*!n+apply(d->(d+2)%10,n=digits(n))*vector(#n,i,10^(#n-i)) \\ M. F. Hasler, Mar 25 2015

Formula

A169931 = A048379 o A048379 (function A048379 applied twice). - M. F. Hasler, Mar 25 2015