A128244 - OEIS

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A128244

Let be s the sum of the digits of n; a(n) is the product of the digits of s.

1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 3, 4, 5, 6 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,2`
	COMMENTS	`The sequence is equal to A053837 up to the 488th term.`
	EXAMPLE	`a(345)=2 because 3+4+5=12 and 1*2=2`
	MAPLE	`P:=proc(n) local i, k, w; for i from 1 by 1 to n do w:=0; k:=i; while k>0 do w:=w+k-(trunc(k/10)10); k:=trunc(k/10); od; k:=w; w:=1; while k>0 do w:=w(k-(trunc(k/10)*10)); k:=trunc(k/10); od; print(w); od; end: P(500);`
	CROSSREFS	`Cf. A053837.` `Sequence in context: A071650 A037265 A053837 * A010888 A177274 A131650` `Adjacent sequences: A128241 A128242 A128243 * A128245 A128246 A128247`
	KEYWORD	`easy,nonn,base`
	AUTHOR	`Paolo P. Lava & Giorgio Balzarotti (paoloplava(AT)gmail.com), May 03 2007`

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Last modified February 14 06:20 EST 2012. Contains 205570 sequences.