|
Search: id:A062027
|
|
|
| A062027 |
|
a(1) = a(2) = a(3) = 1; and for n>3 a(n) = 1*2*3*4 + 2*3*4*5 + 3*4*5*6 + ... + (n-1)*n*1*2 + n*1*2*3, the sum of the cyclic product of terms taken four at a time, final term being n*1*2*3 = 6n. |
|
+0
1
|
|
| 1, 1, 1, 24, 274, 720, 1680, 3520, 6750, 12048, 20284, 32544, 50154, 74704, 108072, 152448, 210358, 284688, 378708, 496096, 640962, 817872, 1031872, 1288512, 1593870, 1954576, 2377836, 2871456, 3443866, 4104144, 4862040, 5728000
(list; graph; listen)
|
|
|
OFFSET
|
1,4
|
|
|
FORMULA
|
a(n) = (n+1)(n)(n-1)(n-2)(n-3)/5 + n(n^2 -n +6).
|
|
EXAMPLE
|
a(5) = 1*2*3*4 + 2*3*4*5 + 3*4*5*1 + 4*5*1*2 + 5*1*2*3 = 274.
|
|
CROSSREFS
|
Adjacent sequences: A062024 A062025 A062026 this_sequence A062028 A062029 A062030
Sequence in context: A001413 A022065 A125412 this_sequence A000915 A006665 A010940
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jun 02 2001
|
|
EXTENSIONS
|
More terms from Jason Earls (jcearls(AT)cableone.net), Jun 07 2001
|
|
|
Search completed in 0.002 seconds
|
