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A005387 Number of partitional matroids on n elements.
(Formerly M1493)
2

%I M1493

%S 1,2,5,16,62,276,1377,7596,45789,298626,2090910,15621640,123897413,

%T 1038535174,9165475893,84886111212,822648571314,8321077557124,

%U 87648445601429,959450073912136,10894692556576613,128114221270929646

%N Number of partitional matroids on n elements.

%D Recski, A.; Enumerating partitional matroids. Stud. Sci. Math. Hungar. 9 (1974), 247-249 (1975).

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H T. D. Noe, <a href="/A005387/b005387.txt">Table of n, a(n) for n=0..100</a>

%H A. Recski, <a href="/A005387/a005387_1.pdf">Enumerating partitional matroids</a>, Preprint.

%H A. Recski & N. J. A. Sloane, <a href="/A005387/a005387.pdf">Correspondence, 1975</a>

%H <a href="/index/Mat#matroid">Index entries for sequences related to matroids</a>

%F E.g.f.: exp ((x-1)*e^x + 2*x + 1 ).

%t With[{nn=30},CoefficientList[Series[Exp[(x-1)E^x+2x+1],{x,0,nn}],x]Range[0,nn]!] (* _Harvey P. Dale_, Nov 22 2012 *)

%K nonn,easy,nice

%O 0,2

%A _N. J. A. Sloane_.

%E More terms from _James A. Sellers_, Aug 21 2000

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Last modified May 17 21:11 EDT 2021. Contains 343990 sequences. (Running on oeis4.)