The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A117270 Matrix log of triangle M = A117269, which satisfies: M - (M-I)^2 = C where C is Pascal's triangle. 2
 0, 1, 0, 2, 2, 0, 12, 6, 3, 0, 134, 48, 12, 4, 0, 2100, 670, 120, 20, 5, 0, 42302, 12600, 2010, 240, 30, 6, 0, 1041852, 296114, 44100, 4690, 420, 42, 7, 0, 30331814, 8334816, 1184456, 117600, 9380, 672, 56, 8, 0, 1019056260, 272986326, 37506672, 3553368 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 COMMENTS E.g.f. of column 0 (A117271) is log( (3-sqrt(5-4*exp(x)))/2 ) and equals the log of the g.f. of column 0 of A117269. LINKS FORMULA T(n,k) = A117271(n-k)*C(n,k). EXAMPLE Triangle begins: 0; 1,0; 2,2,0; 12,6,3,0; 134,48,12,4,0; 2100,670,120,20,5,0; 42302,12600,2010,240,30,6,0; 1041852,296114,44100,4690,420,42,7,0; ... PROG (PARI) {a(n)=local(C=matrix(n+1, n+1, r, c, if(r>=c, binomial(r-1, c-1))), M=C, L); for(i=1, n+1, M=(M-M^0)^2+C); L=sum(r=1, #M, -(M^0-M)^r/r); return(L[n+1, 1])} CROSSREFS Cf. A117269, A117271 (column 0). Sequence in context: A019265 A285539 A285783 * A244137 A181389 A091466 Adjacent sequences:  A117267 A117268 A117269 * A117271 A117272 A117273 KEYWORD nonn,tabl AUTHOR Paul D. Hanna, Mar 05 2006 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 20 01:28 EDT 2020. Contains 337238 sequences. (Running on oeis4.)