OFFSET
0,2
COMMENTS
The identity (392*n + 1)^2 - (196*n^2 + n)*28^2 = 1 can be written as a(n)^2 - (n*A158223(n))*28^2 = 1. - Vincenzo Librandi, Feb 23 2012
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..10000 (corrected by Ray Chandler, Jan 19 2019)
Index entries for linear recurrences with constant coefficients, signature (2,-1).
FORMULA
G.f.: x*(393-x)/(1-x)^2. - Vincenzo Librandi, Feb 10 2012
a(n) = 2*a(n-1) - a(n-2). - Vincenzo Librandi, Feb 10 2012
MATHEMATICA
392Range[40]+1 (* Harvey P. Dale, Jul 24 2011 *)
LinearRecurrence[{2, -1}, {393, 785}, 50] (* Vincenzo Librandi, Feb 10 2012 *)
PROG
(Magma) I:=[393, 785]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..50]]; // Vincenzo Librandi, Feb 10 2012
(PARI) for(n=1, 50, print1(392*n + 1", ")); \\ Vincenzo Librandi, Feb 10 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Mar 11 2009
EXTENSIONS
Extended to a(0)=1 by M. F. Hasler, Jan 04 2014
STATUS
approved