A080463 Sum of the two numbers formed by alternate digits of n.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 8, 9, 10, 11, 12, 13, 14, 15, 16

Offset: 0

Author

Amarnath Murthy, Mar 02 2003

Keywords

• base
• easy
• nonn
• look

Comments

First 99 terms match with those of A007953.

They also match A209685. - M. F. Hasler, Jan 10 2016

Examples

			a(132546) = 124 + 356 = 480.
		

Links

• M. F. Hasler, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A007953, A080464, A080465.

Programs

Maple

f:= proc(n) option remember; n mod 10 + (floor(n/10) mod 10) + 10*procname(floor(n/100)) end proc:
f(0):= 0:
seq(f(n),n=0..1000); # Robert Israel, Jan 10 2016

PARI

A080463(n)=abs(vector(#n=digits(n),j,10^((#n-j)\2))*n~) \\ M. F. Hasler, Jan 10 2016

Formula

From Robert Israel, Jan 10 2016: (Start)

f(n) = n mod 10 + floor(n/10) mod 10 + 10*f(floor(n/100)).

G.f. G(x) satisfies G(x) = (x + 2x^2 + ... + 9x^9)/(1-x^10) + (x^10 + 2 x^20 + ... + 9 x^90)/((1-x)(1+x^10+...+x^90) + 10 (1 + x + ... + x^99) G(x^10).

(End)

Extensions

More terms from Ray Chandler, Oct 11 2003

Extended to offset 0 and b-file by M. F. Hasler, Jan 10 2016