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 A208770 Areas of triangle ABC, if it can be split by two straight lines through A and B, into 4 parts all with integer areas. 0
 6, 12, 15, 18, 20, 21, 24, 28, 30, 35, 36, 40, 42, 44, 45, 48, 52, 54, 56, 60, 63, 65, 66, 70, 72, 75, 77, 78, 80, 84, 85, 88, 90, 91, 95, 96, 99, 100, 104, 105, 108, 110, 112, 117, 119, 120 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS FORMULA n = a+b+c+d, if d = b*c*(2*a+b+c)/(a^2-b*c) is positive integer. EXAMPLE For n=6, some triangle with that area can be divided by 2 straight lines through A and B, into 4 parts with areas (2,1,1,2) or with areas (3,1,1,1). A triangle with area 12 can be divided into parts (2,1,2,7), (3,1,3,5), (4,2,2,4) and (6,2,2,2). Triangles with area 13 or 14 cannot be divided in this way. CROSSREFS Sequence in context: A114304 A175952 A278638 * A219095 A107487 A092671 Adjacent sequences:  A208767 A208768 A208769 * A208771 A208772 A208773 KEYWORD nonn,more AUTHOR Dragan Krejakovic, Mar 01 2012 STATUS approved

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Last modified May 14 05:45 EDT 2021. Contains 343872 sequences. (Running on oeis4.)