%I M3148 #21 Oct 12 2017 19:24:11
%S 3,40,546,7728,112035,1650792,24608948,370084832,5603730876,
%T 85316186400,1304770191802,20029132137840,308437355259930,
%U 4762695514958640,73716196036213800,1143325208566357440,17765127399780725316,276484586847524844768,4309270265307160983144
%N Quadrinomial coefficients.
%D L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 78.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H R. K. Guy, <a href="/A005712/a005712.pdf">Letter to N. J. A. Sloane, 1987</a>
%F a(n) = A008287(2 * n, 3 * n - 1). - _Sean A. Irvine_, Aug 15 2016
%p seq(coeff((1+x+x^2+x^3)^(2*n),x,3*n-1), n=1..30); # _Robert Israel_, Aug 15 2016
%Y Cf. A008287.
%K nonn
%O 1,1
%A _N. J. A. Sloane_
%E Offset changed by _Robert Israel_, Aug 15 2016