OFFSET
1,2
LINKS
Eric Weisstein's World of Mathematics, Twin Pythagorean Triple
EXAMPLE
For a(2)=6 because {3, 4, 5}, {5, 12, 13}, {7, 24, 25}, {9, 40, 41}, {11, 60, 61}, {13, 84, 85}.
MATHEMATICA
f[n_] := Round[ Sqrt[ (10^n - 1)/2] - 1]; Table[ f[n], {n, 25}] (* Robert G. Wilson v, Jan 08 2005 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Eric W. Weisstein, Dec 20 2004
STATUS
approved