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A308214 Sum of the smallest side lengths of all integer-sided obtuse triangles with perimeter n. 1
0, 0, 0, 0, 0, 0, 2, 0, 2, 0, 5, 0, 5, 7, 9, 7, 9, 12, 19, 12, 29, 18, 35, 25, 42, 38, 49, 46, 57, 54, 82, 68, 98, 77, 117, 97, 127, 127, 148, 138, 171, 169, 211, 181, 246, 206, 271, 246, 298, 285, 334, 325, 378, 354, 437, 385, 481, 423, 529, 489, 574, 565 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,7

LINKS

Table of n, a(n) for n=1..62.

Wikipedia, Integer Triangle

FORMULA

a(n) = Sum_{k=1..floor(n/3)} Sum_{i=k..floor((n-k)/2)} (1-sign(floor((i^2 + k^2)/(n-i-k)^2))) * sign(floor((i+k)/(n-i-k+1))) k.

MATHEMATICA

Table[Sum[Sum[k (1 - Sign[Floor[(i^2 + k^2)/(n - i - k)^2]]) Sign[Floor[(i + k)/(n - i - k + 1)]], {i, k, Floor[(n - k)/2]}], {k, Floor[n/3]}], {n, 100}]

CROSSREFS

Cf. A308157.

Sequence in context: A079200 A011420 A035686 * A327371 A037228 A002117

Adjacent sequences:  A308211 A308212 A308213 * A308215 A308216 A308217

KEYWORD

nonn

AUTHOR

Wesley Ivan Hurt, May 15 2019

STATUS

approved

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Last modified April 18 02:38 EDT 2021. Contains 343072 sequences. (Running on oeis4.)