%I #10 Mar 24 2020 07:44:53
%S 0,0,0,1,8,60,440,3290,25424,204120,1705680,14836470,134240040,
%T 1262060228,12313382536,124509169330,1303109358880,14098102762160,
%U 157473907149600,1813923418494126,21523529286435000,262809607270736540
%N Fourth column of PE^2.
%C Base matrix is in A011971; second power is in A078937; third power is in A078938; fourth power is in A078939.
%F PE=exp(matpascal(5))/exp(1); A = PE^2; a(n)=A[n,4] with exact integer arithmetic: PE=exp(matpascal(5)-matid(6)); A = PE^2; a(n)=A[n,4]
%p A056857 := proc(n,c) combinat[bell](n-1-c)*binomial(n-1,c) ; end: A078937 := proc(n,c) add( A056857(n,k)*A056857(k+1,c),k=0..n) ; end: A129325 := proc(n) A078937(n+1,3) ; end: seq(A129325(n),n=0..27) ; # _R. J. Mathar_, May 30 2008
%t A056857[n_, c_] := If[n <= c, 0, BellB[n - 1 - c] Binomial[n - 1, c]];
%t A078937[n_, c_] := Sum[A056857[n, k] A056857[k + 1, c], {k, 0, n}];
%t a[n_] := A078937[n + 1, 3];
%t a /@ Range[0, 21] (* _Jean-François Alcover_, Mar 24 2020, after _R. J. Mathar_ *)
%o (PARI) m=matpascal(30)-matid(31); pe=matid(31)+sum(i=1,30,m^i/i!); A=pe^2; A[,4] \\ Herman Jamke (hermanjamke(AT)fastmail.fm), May 01 2008
%Y Cf. A056857, A078937, A078938, A078944, A078945, A000110.
%Y Cf. A078937, A078938, A129323, A129324, A129325, A027710.
%Y Cf. A129327, A129328, A129329, A078944, A129331, A129332, A129333.
%K nonn,easy
%O 0,5
%A _Gottfried Helms_, Apr 08 2007
%E More terms from _R. J. Mathar_ and Herman Jamke (hermanjamke(AT)fastmail.fm), May 01 2008