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A308216 Sum of the largest side lengths of all integer-sided obtuse triangles with perimeter n. 1
0, 0, 0, 0, 0, 0, 3, 0, 4, 0, 10, 0, 12, 12, 21, 14, 24, 24, 44, 27, 67, 40, 85, 54, 104, 82, 126, 101, 149, 123, 201, 160, 244, 187, 292, 230, 327, 294, 382, 329, 439, 403, 539, 444, 625, 508, 699, 594, 775, 688, 879, 786, 986, 869, 1124, 954, 1244, 1071 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,7

LINKS

Table of n, a(n) for n=1..58.

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))) (n-i-k).

MATHEMATICA

Table[Sum[Sum[(n - i - 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. A308214.

Sequence in context: A289445 A237558 A060034 * A035544 A129718 A127375

Adjacent sequences:  A308213 A308214 A308215 * A308217 A308218 A308219

KEYWORD

nonn

AUTHOR

Wesley Ivan Hurt, May 15 2019

STATUS

approved

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Last modified January 24 00:05 EST 2022. Contains 350515 sequences. (Running on oeis4.)