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

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A117474 The values of 'a' in a^2 + b^2 = c^2 where b - a = 7 and gcd(a,b,c)=1. 1
5, 8, 48, 65, 297, 396, 1748, 2325, 10205, 13568, 59496, 79097, 346785, 461028, 2021228, 2687085, 11780597, 15661496, 68662368, 91281905, 400193625, 532029948, 2332499396, 3100897797, 13594802765, 18073356848 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

The values of 'c' are in A060569

FORMULA

a(1)=5, a(2)=8, a(3)=48, a(4)=65, a(n) = 6*a(n-2) - a(n-4) + 14

EXAMPLE

a(5) = 6*48 - 5 + 14 = 297 and 297^2 + 304^2 = 425^2 and 304 -297 = 7 and gcd(297, 304, 425) = 1

MAPLE

g:=proc(n) option remember; if n=1 then RETURN(5) fi; if n=2 then RETURN(8) fi; if n=3 then RETURN(48) fi; if n=4 then RETURN(65) fi; 6*g(n-2)-g(n-4)+14; end; [N. J. A. Sloane, Oct 06 2007]

CROSSREFS

Cf. A060569.

Sequence in context: A126750 A109292 A192379 * A165716 A068478 A132050

Adjacent sequences:  A117471 A117472 A117473 * A117475 A117476 A117477

KEYWORD

nonn

AUTHOR

Andras Erszegi (erszegi.andras(AT)chello.hu), Mar 19 2006

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 16 13:47 EST 2012. Contains 205919 sequences.