A038802 - OEIS

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A038802

Factor 2n+1 = (2^m1)*(3^m2)*(5^m3)*...; a(n) = number of initial zero exponents.

1, 2, 3, 1, 4, 5, 1, 6, 7, 1, 8, 2, 1, 9, 10, 1, 2, 11, 1, 12, 13, 1, 14, 3, 1, 15, 2, 1, 16, 17, 1, 2, 18, 1, 19, 20, 1, 3, 21, 1, 22, 2, 1, 23, 3, 1, 2, 24, 1, 25, 26, 1, 27, 28, 1, 29, 2, 1, 3, 4, 1, 2, 30, 1, 31, 3, 1, 32, 3, 3, 1, 4, 2, 1, 34, 35, 1, 2, 36, 1, 3, 37, 1, 38, 5, 1, 39, 2, 1, 40 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	FORMULA	`a(n) = A049084(A020639(2n+1))-1. - R. J. Mathar, Mar 01 2011`
	EXAMPLE	`9 = (2^0)*(3^2), thus a(4) = 1.`
	MAPLE	`A038802 := proc(n) numtheory[factorset](2*n+1) ; min(%); numtheory[pi](%)-1 ; end proc: # R. J. Mathar, Mar 01 2011`
	CROSSREFS	`Sequence in context: A055446 A104706 A094137 * A092942 A131225 A137671` `Adjacent sequences: A038799 A038800 A038801 * A038803 A038804 A038805`
	KEYWORD	`nonn`
	AUTHOR	`Thomas Kellar (tkellar(AT)fsp.com)`

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Last modified February 16 17:48 EST 2012. Contains 205939 sequences.