A175342 - OEIS

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A175342

Number of arithmetic progressions (where the difference between adjacent terms is either positive, 0, or negative) of positive integers that sum to n.

1, 2, 4, 5, 6, 10, 8, 10, 15, 14, 12, 22, 14, 18, 28, 21, 18, 34, 20, 28, 38, 28, 24, 46, 31, 32, 48, 38, 30, 62, 32, 40, 58, 42, 46, 73, 38, 46, 68, 58, 42, 84, 44, 56, 90, 56, 48, 94, 55, 70, 90, 66, 54, 106, 70, 74, 100, 70, 60, 130, 62, 74, 118, 81, 82, 130, 68, 84, 120 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`1,2`
	LINKS	`Lars Blomberg, Table of n, a(n) for n = 1..10000` `Lars Blomberg, C# program for calculating b-file`
	FORMULA	`a(n) = 2A049988(n) - A000005(n).` `G.f.: x/(1-x) + Sum_{k>=2} x^k (1 + x^(k(k-1)/2)) / (1 - x^(k(k-1)/2)) / (1 -x^k).`
	CROSSREFS	`Cf. A049988, A175327.` `Sequence in context: A136585 A122721 A014224 * A077312 A140779 A117890` `Adjacent sequences: A175339 A175340 A175341 * A175343 A175344 A175345`
	KEYWORD	`nonn`
	AUTHOR	`Leroy Quet, Apr 17 2010`
	EXTENSIONS	`Edited and extended by Max Alekseyev, May 03 2010`
	STATUS	`approved`

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Last modified March 1 18:27 EST 2015. Contains 255123 sequences.