OFFSET
1,1
COMMENTS
a(n) where n is divisible by k will not exceed a(k)*n/k. A consequence of this is that even if n is prime, a(n) will not exceed 305n (since a(1) = 305).
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..10000
EXAMPLE
a(17) = 5185 because the smallest Pythagorean triple whose legs are m and 2m + 17 has hypotenuse 5185. m in this case = 2312, and 2m + 17 = 4641.
MATHEMATICA
a[n_] := Block[{k = 1, h}, While[h = 5*k^2 + 4*k*n + n^2; Round[Sqrt@N@h]^2 != h, k++]; Sqrt@h]; Array[a, 50] (* Giovanni Resta, Mar 15 2013 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Elliott Line, Mar 15 2013
STATUS
approved