login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A125302 Nonprime numbers n such that n cannot be a semiperimeter of an integer Heronian triangle. 0
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; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Trivially, no prime number can be a semiperimeter of an integer Heronian triangle. Therefore primes are excluded from the sequence.
LINKS
Eric Weisstein's World of Mathematics, Heronian Triangle.
MAPLE
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);
CROSSREFS
Sequence in context: A051741 A022382 A162521 * A365679 A175588 A239788
KEYWORD
nonn
AUTHOR
Seppo Mustonen, Jan 17 2007
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 14 16:43 EDT 2024. Contains 374322 sequences. (Running on oeis4.)