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A138707 Number of divisors of n that are also divisors of some d(k)*10^k, where n=Sum(d(k)*10^k). 4
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 (list; graph; refs; listen; history; text; internal format)
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: A087990 A335037 A179940 * A095048 A332268 A084302

Adjacent sequences:  A138704 A138705 A138706 * A138708 A138709 A138710

KEYWORD

nonn,base

AUTHOR

Reinhard Zumkeller, Mar 26 2008

STATUS

approved

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Last modified April 14 05:22 EDT 2021. Contains 342943 sequences. (Running on oeis4.)