A138707 Number of divisors of n that are also divisors of some d(k)*10^k, where n=Sum(d(k)*10^k).

1, 2, 2, 3, 2, 4, 2, 4, 3, 4, 1, 2, 1, 2, 2, 2, 1, 2, 1, 6, 1, 2, 1, 3, 2, 2, 1, 3, 1, 8, 1, 2, 2, 2, 2, 4, 1, 2, 2, 8, 1, 2, 1, 3, 2, 2, 1, 4, 1, 6, 1, 2, 1, 2, 2, 2, 1, 2, 1, 12, 1, 2, 2, 3, 2, 4, 1, 3, 2, 8, 1, 2, 1, 2, 2, 2, 2, 2, 1, 10, 1, 2, 1, 3, 2, 2, 1, 4, 1, 12, 1, 2, 2, 2, 2, 4, 1, 2, 3, 9, 1, 2, 1, 3

Offset

1,2

Comments

a(A138708(n)) = 1; a(A037124(n)) = A000005(A037124(n)).

Links

R. Zumkeller, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Divisor Function

Example

n = 216 = 2*10^2 + 1*10^1 + 6*10^0: let D(n) = set of divisors of
n,
D(216)={1,2,3,4,6,8,9,12,18,24,27,36,54,72,108,216},
D(200)={1,2,4,5,8,10,20,25,40,50,100,200}, D(10)={1,2,5,10}, D(6)={1,2,3,6},
a(216) = #{1,2,3,4,6,8} = 6.

Crossrefs

Cf. A061116.

Sequence in context: A335037 A356069 A179940 * A358099 A095048 A332268

Adjacent sequences: A138704 A138705 A138706 * A138708 A138709 A138710

Keyword

nonn,base

Author

Reinhard Zumkeller, Mar 26 2008

Status

approved