|
Search: id:A063258
|
|
| |
|
| 4, 14, 34, 69, 125, 209, 329, 494, 714, 1000, 1364, 1819, 2379, 3059, 3875, 4844, 5984, 7314, 8854, 10625, 12649, 14949, 17549, 20474, 23750, 27404, 31464, 35959, 40919, 46375, 52359, 58904, 66044
(list; graph; listen)
|
|
|
OFFSET
|
0,1
|
|
|
COMMENT
|
In the Frey-Sellers reference this sequence is called {(n+2) over 4}_{3}, n >= 0.
If X is an n-set and Y a fixed (n-4)-subset of X then a(n-5) is equal to the number of 4-subsets of X intersecting Y. - Milan R. Janjic (agnus(AT)blic.net), Aug 15 2007
|
|
REFERENCES
|
D. D. Frey and J. A. Sellers, Generalizing Bailey's generalization of the Catalan numbers, The Fibonacci Quarterly, 39 (2001) 142-148.
|
|
LINKS
|
Milan Janjic, Two Enumerative Functions
|
|
FORMULA
|
a(n)= A062750(n+2, 4)= (n+6)*(n+1)*(n^2+7*n+16)/4!.
G.f.: N(4;1, x)/(1-x)^5 with N(4;1, x)= 4-6*x+4*x^2-x^3, polynomial of second row of A062751.
|
|
MAPLE
|
[seq(binomial(n, 4)-1, n=5..37)]; - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Nov 25 2006
|
|
CROSSREFS
|
Fifth column (r=4) of FS(4) staircase array A062750.
A column of triangle A014473.
Cf. A000096, A062748.
Sequence in context: A098942 A011554 A099586 this_sequence A011852 A061989 A079908
Adjacent sequences: A063255 A063256 A063257 this_sequence A063259 A063260 A063261
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de), Jul 12 2001
|
|
EXTENSIONS
|
Simpler definition from Vladeta Jovovic (vladeta(AT)Eunet.yu), Jul 21 2003
More terms from Milan R. Janjic (agnus(AT)blic.net), Aug 15 2007
|
|
|
Search completed in 0.002 seconds
|
