|
Search: id:A113772
|
|
|
| A113772 |
|
Determinant of the 2 X 2 matrices where the first column is consecutive triangular numbers and the second column is the corresponding consecutive fibonacci numbers. |
|
+0
1
|
|
| -2, 0, -2, 5, 15, 49, 120, 279, 605, 1265, 2562, 5070, 9842, 18810
(list; graph; listen)
|
|
|
OFFSET
|
2,1
|
|
|
FORMULA
|
a(n) = t(n-1)*f(n)-t(n)*f(n-1) where t(n)=n(n+1)/2 and f(n)=f(n-1)+f(n-2) and f(1)=1 and f(2)=1
|
|
EXAMPLE
|
a(5) = t(4)*f(5)-t(5)*f(4) = 10*5-15*3 = 50-45 = 5
|
|
CROSSREFS
|
Sequence in context: A110282 A024308 A059432 this_sequence A033716 A115978 A033751
Adjacent sequences: A113769 A113770 A113771 this_sequence A113773 A113774 A113775
|
|
KEYWORD
|
easy,sign
|
|
AUTHOR
|
Patrick J. Costello (pat.costello(AT)eku.edu), Jan 19 2006
|
|
|
Search completed in 0.002 seconds
|
