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 A173221 Column 0 of triangle A173220. 4
 0, 1, 2, 60, 3528, 377620, 63642600, 15485843814, 5128034120832, 2214330161840640, 1207205860726123200, 810202288257005858280, 655934516902959161345280, 630002861547863478457648320 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Triangle A173220 is the matrix log of triangle T = A173210, which satisfies: row n of T^n = row n of (I+D)^(n^2) where D is the lower diagonal matrix: D(n+1,n)=n+1. LINKS PROG (PARI) {a(n)=local(M=Mat(1), N, L=Mat(1), C=matrix(n+2, n+2, r, c, if(r==c, 1, if(r==c+1, c)))); for(i=1, n+1, N=M; M=matrix(#N+1, #N+1, r, c, if(r>=c, if(r<=#N, (N^(#N))[r, c], (C^((#M)^2))[r, c]))); L=sum(i=1, #M, -(M^0-M)^i/i); M=sum(i=0, #M, (L/#N)^i/i!); ); L[n+1, 1]/(n+1)} CROSSREFS Cf. A173220, A173222, A173223, A173224. Sequence in context: A227624 A199643 A056923 * A082787 A078423 A231024 Adjacent sequences:  A173218 A173219 A173220 * A173222 A173223 A173224 KEYWORD nonn,tabl AUTHOR Paul D. Hanna, Feb 12 2010 STATUS approved

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