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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
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) = 2*A049988(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 September 1 03:50 EDT 2014. Contains 246282 sequences.