|
Search: id:A075878
|
|
|
| A075878 |
|
Sum of coefficients of (x1)^(2i(1))*(x2)^(2i(2))*(x3)^(2i(3))*(x4)^(2i(4)) for {(i1),(i2),(i3),(i4)}=0,1,2,... : sum(i)=2n in the expansion of (x1+x2+x3+x4)^(2n) where n=1,2,3,... |
|
+0
1
|
|
| 4, 40, 544, 8320, 131584, 2099200, 33562624, 536903680, 8590065664, 137439477760, 2199025352704, 35184380477440
(list; graph; listen)
|
|
|
OFFSET
|
0,1
|
|
|
COMMENT
|
For k=3, the sequence divided by 3 is equal to A066443.
|
|
FORMULA
|
a(n, 4) = 2^(1-4)*(sum(r=0 to Floor((4-1)/2))Binomial(4, r)*(4-2*r)^2n a(n, k) = 2^(1-k)*(sum(r=0 to Floor((k-1)/2))Binomial(k, r)*(k-2*r)^2n for k=1, 2, 3, 4, ...
|
|
CROSSREFS
|
Cf. A066443.
Sequence in context: A002705 A034385 A074637 this_sequence A092812 A128573 A052675
Adjacent sequences: A075875 A075876 A075877 this_sequence A075879 A075880 A075881
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Jan Hagberg (jan.hagberg(AT)stat.su.se), Oct 16 2002
|
|
EXTENSIONS
|
Corrected by T. D. Noe (noe(AT)sspectra.com), Nov 07 2006
|
|
|
Search completed in 0.002 seconds
|
