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Search: id:A111991
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| 1, 18, 216, 2136, 18864, 154656, 1203072, 9000576, 65339136, 463112704, 3219204096, 22019254272, 148577427456, 990973034496, 6543595044864, 42832379117568, 278217855664128, 1794871415144448, 11508930723708928
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OFFSET
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0,2
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FORMULA
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G.f.: 1/(1-6*x+8*x^3)^3.
a(n)= (2*(n+1)*b(n+1)-(n+6)*b(n)-4*(n+5)*b(n-1))/(2*9), with b(n):=A111990(n).
a(n)= ((35*n^2+75*n+54)*c(n)-4*(n+2)*(2*n-1)*c(n-1)-48*(n+1)^2*c(n-2))/54, with c(n):= A111989(n), especially, c(-2) = 0 = c(-1).
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CROSSREFS
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Cf. A111990 (first convolution of A111989). A112003 (third convolution).
Adjacent sequences: A111988 A111989 A111990 this_sequence A111992 A111993 A111994
Sequence in context: A021764 A059357 A009470 this_sequence A081136 A101188 A019757
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KEYWORD
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nonn,easy
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AUTHOR
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Wolfdieter Lang (wolfdieter.lang_AT_physik_DOT_uni-karlsruhe_DOT_de), Sep 12 2005
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