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A371972
a(n) is the number of distinct areas of triangles with integer sides whose largest side is n.
1
1, 2, 4, 6, 9, 12, 16, 20, 25, 30, 36, 42, 49, 56, 64, 72, 81, 90, 100, 110, 120, 131, 144, 156, 168, 182, 196, 210, 225, 239, 256, 270, 288, 306, 321, 342, 361, 380, 399, 420, 441, 460, 484, 505, 527, 552, 576, 599, 623, 649, 673, 702, 729, 752, 781, 808, 840, 870, 900
OFFSET
1,2
FORMULA
a(n) <= A002620(n+1), with equality for n <= 20.
PROG
(PARI) A2(a, b, c) = {my(s=(a+b+c)/2); s*(s-a)*(s-b)*(s-c)};
a371972(n) = {my (A=List()); for(s2=1, n, for(s3=1, s2, if(s2+s3>n, listput(A, A2(n, s2, s3))))); #Set(A)};
CROSSREFS
KEYWORD
nonn
AUTHOR
Hugo Pfoertner, Apr 16 2024
STATUS
approved