A093640 - OEIS

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A093640

Number of divisors of n whose binary representation is contained in that of n.

1, 2, 2, 3, 2, 4, 2, 4, 2, 4, 2, 6, 2, 4, 3, 5, 2, 4, 2, 6, 2, 4, 2, 8, 2, 4, 3, 6, 2, 6, 2, 6, 2, 4, 2, 6, 2, 4, 3, 8, 2, 4, 2, 6, 4, 4, 2, 10, 2, 4, 3, 6, 2, 6, 4, 8, 3, 4, 2, 9, 2, 4, 4, 7, 2, 4, 2, 6, 2, 4, 2, 8, 2, 4, 4, 6, 2, 6, 2, 10, 2, 4, 2, 6, 3, 4, 3, 8, 2, 8, 3, 6, 3, 4, 3, 12, 2, 4, 3, 6, 2 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`a(n)>1 for n>1; a(p) =2 for primes p.` `a(A093641(n)) =A000005(A093641(n)), a(A093642(n)) < A000005(A093642(n)).`
	LINKS	`Index entries for sequences related to binary expansion of n` `Reinhard Zumkeller, Table of n, a(n) for n = 1..10000`
	EXAMPLE	`n=18: divisors of 18: 1='1', 2='10', 3='11', 6='110', 9='1001' and 18='10010': four of them are binary substrings of '10010', therefore a(18) =4.`
	PROG	`(Haskell)` `import Data.List (isInfixOf)` `a093640 n = length [d \| d <- [1..n], mod n d == 0,` show (a007088 d) `isInfixOf` show (a007088 n)] `-- Reinhard Zumkeller, Jan 22 2012`
	CROSSREFS	`Cf. A078822, A007088.` `Sequence in context: A043261 A157986 A025479 * A083903 A083867 A076888` `Adjacent sequences: A093637 A093638 A093639 * A093641 A093642 A093643`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Apr 07 2004`

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Last modified February 17 19:13 EST 2012. Contains 206085 sequences.