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 A070086 Areas of integer triangles [A070080(n), A070081(n), A070082(n)], rounded values. 13
 0, 1, 2, 1, 2, 3, 2, 3, 4, 4, 4, 2, 4, 4, 6, 5, 6, 7, 3, 5, 5, 7, 8, 6, 7, 8, 9, 3, 6, 6, 9, 7, 10, 11, 7, 9, 10, 11, 12, 4, 6, 8, 10, 8, 12, 12, 14, 8, 10, 12, 13, 12, 15, 16, 4, 7, 9, 12, 10, 14, 10, 15, 16, 17, 9, 12, 13, 15, 14, 17, 18, 19, 5, 8, 10 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Triangles [A070080(A070142(n)), A070081(A070142(n)), A070082(A070142(n))] have integer areas = a(A070142(k)) = A070149(k). LINKS Eric Weisstein's World of Mathematics, Heron's Formula. R. Zumkeller, Integer-sided triangles FORMULA a(n) = sqrt(s*(s-u)*(s-v)*(s-w)), where u=A070080(n), v=A070081(n), w=A070082(n) and s = A070083(n)/2 = (u+v+w)/2. EXAMPLE [A070080(25), A070081(25), A070082(25)] = [3,5,6] and s = A070083(25)/2 = (3+5+6)/2 = 7: a(25) = sqrt(s*(s-3)*(s-5)*(s-6)) = sqrt(7*(7-3)*(7-5)*(7-6)) = sqrt(7*4*2*1) = sqrt(56) = 7.48331, rounded = 7. CROSSREFS Cf. A051516, A055595, A069596, A069594, A046131. Sequence in context: A008611 A025798 A161064 * A211990 A162618 A036576 Adjacent sequences:  A070083 A070084 A070085 * A070087 A070088 A070089 KEYWORD nonn AUTHOR Reinhard Zumkeller, May 05 2002 STATUS approved

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Last modified October 23 06:48 EDT 2019. Contains 328335 sequences. (Running on oeis4.)