|
|
A157516
|
|
a(n) = 5000*n^2 - 200*n + 1.
|
|
3
|
|
|
4801, 19601, 44401, 79201, 124001, 178801, 243601, 318401, 403201, 498001, 602801, 717601, 842401, 977201, 1122001, 1276801, 1441601, 1616401, 1801201, 1996001, 2200801, 2415601, 2640401, 2875201, 3120001, 3374801, 3639601
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
The identity (5000*n^2 - 200*n + 1)^2 - (25*n^2 - n)*(1000*n - 20)^2 = 1 can be written as a(n)^2 - A157514(n)*A157515(n)^2 = 1 (see also the second part of the comment at A157514). - Vincenzo Librandi, Jan 26 2012
|
|
LINKS
|
|
|
FORMULA
|
|
|
MATHEMATICA
|
LinearRecurrence[{3, -3, 1}, {4801, 19601, 44401}, 50] (* Vincenzo Librandi, Jan 26 2012 *)
|
|
PROG
|
(Magma) I:=[4801, 19601, 44401]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+1*Self(n-3): n in [1..50]]; // Vincenzo Librandi, Jan 26 2012
(PARI) for(n=1, 22, print1(5000*n^2 - 200*n + 1", ")); \\ Vincenzo Librandi, Jan 26 2012
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|