OFFSET
0,8
COMMENTS
Not all colors need to be used.
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..1274
R. C. Read, E. M. Wright, Colored graphs: A correction and extension, Canad. J. Math. 22 1970 594-596.
FORMULA
EXAMPLE
Array begins:
===============================================================
n\k| 0 1 2 3 4 5 6
---+-----------------------------------------------------------
0 | 1 1 1 1 1 1 1 ...
1 | 0 1 2 3 4 5 6 ...
2 | 0 0 2 6 12 20 30 ...
3 | 0 0 6 42 132 300 570 ...
4 | 0 0 38 618 3156 9980 24330 ...
5 | 0 0 390 15990 136980 616260 1956810 ...
6 | 0 0 6062 668526 10015092 65814020 277164210 ...
7 | 0 0 134526 43558242 1199364852 11878194300 67774951650 ...
...
PROG
(PARI)
M(n)={
my(p=sum(j=0, n, x^j/(j!*2^binomial(j, 2))) + O(x*x^n));
my(q=sum(j=0, n, x^j*2^binomial(j, 2)) + O(x*x^n));
my(W=Mat(vector(n, k, Col(serlaplace(1 + log(serconvol(q, p^k)))))));
matconcat([1, W]);
}
my(T=M(7)); for(n=1, #T, print(T[n, ]))
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Andrew Howroyd, Dec 01 2018
STATUS
approved