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Search: id:A125302
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| A125302 |
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Nonprime numbers n such that n cannot be a semiperimeter of an integer Heronian triangle. |
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+0
1
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| 1, 4, 10, 14, 26, 46, 51, 58, 62, 69, 74, 92, 94, 106, 122, 123, 141, 142, 158, 188, 202, 206, 213, 218, 254, 267, 284, 298, 302, 314, 329, 334, 339, 346, 355, 362, 365, 382, 394, 398, 411, 446, 458, 478, 485, 501, 526, 538, 542, 554, 573, 586, 622, 634, 668
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Trivially, no prime number can be a semiperimeter of an integer Heronian triangle. Therefore primes are excluded from the sequence.
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LINKS
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Eric Weisstein's World of Mathematics, Heronian Triangle.
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MAPLE
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notriangle:=proc(n::nonnegint) local a, b, c; if type(n, prime) then RETURN(false) fi; for a from floor(2*n/3) to n-1 do for b from floor(n-a/2) to a do c:=2*n-a-b; if type(sqrt(n*(n-a)*(n-b)*(n-c)), integer) then RETURN(false); fi; od; od; RETURN(true); end: N:=100: a:=array[1..N]: i:=0: n:=0: while i<N do n:=n+1; if notriangle(n) then i:=i+1; a[i]:=n; fi; od: seq(a[i], i=1..N);
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CROSSREFS
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Sequence in context: A051741 A022382 A162521 this_sequence A136862 A123925 A106668
Adjacent sequences: A125299 A125300 A125301 this_sequence A125303 A125304 A125305
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KEYWORD
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nonn
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AUTHOR
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Seppo Mustonen (seppo.mustonen(AT)helsinki.fi), Jan 17 2007
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