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A070138 Number of integer triangles with an integer area having relatively prime sides a, b and c such that a + b + c = n. 9
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 2, 0, 0, 0, 1, 0, 2, 0, 1, 0, 0, 0, 1, 0, 2, 0, 0, 0, 3, 0, 1, 0, 0, 0, 1, 0, 0, 0, 3, 0, 1, 0, 1, 0, 2, 0, 1, 0, 0, 0, 1, 0, 1, 0, 2, 0, 0, 0, 5, 0, 0, 0, 0, 0, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,36

COMMENTS

From Peter Kagey, Jan 30 2018: (Start)

a(k) > 0 if and only if k is in A096468.

Records appear at indices 12, 36, 54, 84, 98, 162, 242, 338, 484, 578, ....

a(2k - 1) = 0 for all integers k > 0.

(End)

LINKS

Peter Kagey, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Heronian Triangle.

R. Zumkeller, Integer-sided triangles

CROSSREFS

Cf. A051493, A051516, A070088, A070109, A070143, A096468, A239246.

Sequence in context: A208575 A070203 A070201 * A024153 A079127 A056674

Adjacent sequences:  A070135 A070136 A070137 * A070139 A070140 A070141

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, May 05 2002

EXTENSIONS

Corrected by T. D. Noe, Jun 17 2004

STATUS

approved

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Last modified March 23 16:52 EDT 2019. Contains 321432 sequences. (Running on oeis4.)