login
This site is supported by donations to The OEIS Foundation.
Logo

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A158744 a(n)=74*n^2-1. 1
73, 295, 665, 1183, 1849, 2663, 3625, 4735, 5993, 7399, 8953, 10655, 12505, 14503, 16649, 18943, 21385, 23975, 26713, 29599, 32633, 35815, 39145, 42623, 46249, 50023, 53945, 58015, 62233, 66599, 71113, 75775, 80585, 85543, 90649, 95903 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

The identity (74*n^2-1)^2 - (1369*n^2-37) * (2*n)^2 = 1 can be written as

the Pell equation (a(n))^2 - A158743(n) * (A005843(n))^2 = 1.

LINKS

Wolfram MathWorld, Pell Equation

Vincenzo Librandi, X^2-AY^2=1

Edward Everett Withford, Pell Equation

CROSSREFS

Cf. A005843, A158743

Sequence in context: A158740 A174334 A142614 * A142406 A005108 A142810

Adjacent sequences:  A158741 A158742 A158743 * A158745 A158746 A158747

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 25 2009

EXTENSIONS

a(n)= 3*a(n-1) -3*a(n-2) +a(n-3). G.f.: x*(-73-76*x+x^2)/(x-1)^3.

Comment rewritten and formula replaced by R. J. Mathar, (mathar(AT)strw.leidenuniv.nl), Oct 22 2009

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified February 14 08:58 EST 2012. Contains 205614 sequences.