The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

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