id:A131809 - OEIS Search Results

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Multiplicative persistence of Catalan numbers.

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0, 0, 0, 0, 1, 1, 1, 3, 1, 5, 4, 2, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 (list; graph; listen)

	OFFSET	`0,8`
	COMMENT	`After the 57th terms all the numbers have some digits equal to zero thus the persistence is equal to 1.`
	EXAMPLE	`Catalan number 429 -> 429=72 -> 72=14 -> 14=4 thus persistence is 3`
	MAPLE	`P:=proc(n) local i, k, w, ok, cont; for i from 0 by 1 to n do k:=(2i)!/(i!(i+1)!); w:=1; ok:=1; if k<10 then print(0); else cont:=1; while ok=1 do while k>0 do w:=w(k-(trunc(k/10)10)); k:=trunc(k/10); od; if w<10 then ok:=0; print(cont); else cont:=cont+1; k:=w; w:=1; fi; od; fi; od; end: P(100);`
	CROSSREFS	`Cf. A003001, A006050, A000108.` `Sequence in context: A029655 A110813 A124883 this_sequence A016574 A068512 A011090` `Adjacent sequences: A131806 A131807 A131808 this_sequence A131810 A131811 A131812`
	KEYWORD	`easy,nonn,base`
	AUTHOR	`Paolo P. Lava & Giorgio Balzarotti (ppl(AT)spl.at), Jul 18 2007`

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Last modified December 3 01:16 EST 2008. Contains 151161 sequences.

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