A121760 In decimal number system, take negative power of 10 at odd digits of n. Sequence gives numerators of result.

1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 11, 21, 31, 41, 51, 61, 71, 81, 91, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 3, 13, 23, 33, 43, 53, 63, 73, 83, 93, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 7, 17, 27, 37, 47, 57, 67

Offset

1,2

Comments

See accompanying sequence A121761 In decimal number system, take negative power of 10 at even digits of n.

Links

Zak Seidov, First 1000 terms

Formula

If n = sum(d(i)*10^(i-1)), then a(n)=sum(d(i)*10^((-1)^(1+d(i))*(i-1))).

Example

a(12)=21 because 12=1*10^1+2*10^0 and a(12)=numerator[1*10^((-1)^(1)*1)+2*10^((-1)^(0)*0)=1/10+2=21/10]=21.

Crossrefs

Cf. A121761.

Sequence in context: A084011 A345110 A004086 * A061816 A083960 A344486

Adjacent sequences: A121757 A121758 A121759 * A121761 A121762 A121763

Keyword

base,frac,nonn

Author

Zak Seidov, Aug 20 2006

Extensions

a(40) corrected by N. J. A. Sloane, Aug 23 2006

Status

approved