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A121041 Number of divisors of n that are also contained in the decimal representation of n. 38
1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 1, 3, 2, 2, 1, 2, 1, 2, 2, 2, 2, 1, 2, 3, 1, 1, 2, 2, 2, 2, 1, 2, 2, 1, 1, 3, 1, 2, 2, 2, 1, 1, 2, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 2, 2, 2, 1, 1, 2, 1, 2, 1, 1, 2, 2, 2, 1, 2, 2, 1, 1, 2, 1, 2, 2, 2, 2, 1, 2, 2, 1, 1, 2, 3, 2, 3, 2, 3, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,10

COMMENTS

a(n) = 1 iff A121042(n) = n.

a(A155005(n)) = n and a(m) < n for m < A155005(n). - Reinhard Zumkeller, Jan 18 2009

LINKS

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

EXAMPLE

a(22) = #{2, 22} = 2;

a(23) = #{23} = 1;

a(24) = #{2, 4, 24} = 3.

PROG

(Haskell)

import Data.List (isInfixOf)

a121041 n = length $ filter (\d -> n `mod` d == 0

                                   && show d `isInfixOf` show n) [1..n]

-- Reinhard Zumkeller, Feb 11 2011

(PARI) substr(a, b)=a=digits(a); b=digits(b); for(i=0, #a-#b, for(j=1, #b, if(a[i+j]!=b[j], next(2))); return(1)); 0

a(n)=sumdiv(n, d, substr(n, d)) \\ Charles R Greathouse IV, Mar 31 2016

CROSSREFS

Cf. A121022, A121023, A121024, A121025, A121026, A121027, A121028, A121029, A121030, A121031, A121032, A121033, A121034, A121035, A121036, A121037, A121038, A121039, A121040.

Sequence in context: A230578 A089132 A107259 * A157439 A261865 A003589

Adjacent sequences:  A121038 A121039 A121040 * A121042 A121043 A121044

KEYWORD

nonn,base,easy

AUTHOR

Reinhard Zumkeller, Jul 21 2006

STATUS

approved

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Last modified April 19 20:40 EDT 2019. Contains 322291 sequences. (Running on oeis4.)