|
|
A106318
|
|
Bhaskara twins: n such that 2*n^2 = X^3 and 2*n^3 = Y^2.
|
|
7
|
|
|
2, 128, 1458, 8192, 31250, 93312, 235298, 524288, 1062882, 2000000, 3543122, 5971968, 9653618, 15059072, 22781250, 33554432, 48275138, 68024448, 94091762, 128000000, 171532242, 226759808, 296071778, 382205952, 488281250, 617831552
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
REFERENCES
|
S. S. Gupta, 'Bhaskara Pairs' in 'Science Today' (subsequently renamed '2001'), January 1988, pp. 68, Times of India, Mumbai.
|
|
LINKS
|
|
|
FORMULA
|
G.f.: 2*(1+x)*(1+56*x+246*x^2+56*x^3+x^4)/(1-x)^7. - Colin Barker, Apr 18 2012
a(n) = 7*a(n-1)-21*a(n-2)+35*a(n-3)-35*a(n-4)+21*a(n-5)-7*a(n-6)+a(n-7). - Wesley Ivan Hurt, Apr 23 2021
|
|
MATHEMATICA
|
LinearRecurrence[{7, -21, 35, -35, 21, -7, 1}, {2, 128, 1458, 8192, 31250, 93312, 235298}, 30] (* Harvey P. Dale, May 11 2017 *)
|
|
PROG
|
(Haskell)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nice,nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|