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 A167432 Riordan array (c(2x)^2,xc(2x)), c(x) the g.f. of A000108. 2
 1, 4, 1, 20, 6, 1, 112, 36, 8, 1, 672, 224, 56, 10, 1, 4224, 1440, 384, 80, 12, 1, 27456, 9504, 2640, 600, 108, 14, 1, 183040, 64064, 18304, 4400, 880, 140, 16, 1, 1244672, 439296, 128128, 32032, 6864, 1232, 176, 18, 1, 8599552, 3055104, 905216, 232960 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Inverse of (1-4x+4x^2,x(1-2x)) (A167431). Row sums are A084076. First column is A003645. LINKS Table of n, a(n) for n=0..48. FORMULA Number triangle T(n,k)=A054445(n,k)*2^(n-k). EXAMPLE Triangle begins 1, 4, 1, 20, 6, 1, 112, 36, 8, 1, 672, 224, 56, 10, 1, 4224, 1440, 384, 80, 12, 1, 27456, 9504, 2640, 600, 108, 14, 1, 183040, 64064, 18304, 4400, 880, 140, 16, 1, 1244672, 439296, 128128, 32032, 6864, 1232, 176, 18, 1, 8599552, 3055104, 905216, 232960, 52416, 10192, 1664, 216, 20, 1, 60196864, 21498880, 6449664, 1697280, 396032, 81536, 14560, 2184, 260, 22, 1 The production matrix is 4, 1, 4, 2, 1, 8, 4, 2, 1, 16, 8, 4, 2, 1, 32, 16, 8, 4, 2, 1, 64, 32, 16, 8, 4, 2, 1, 128, 64, 32, 16, 8, 4, 2, 1, 256, 128, 64, 32, 16, 8, 4, 2, 1, 512, 256, 128, 64, 32, 16, 8, 4, 2, 1 When topped with the row (1,0,0,0...), this has inverse 1, -4, 1, 4, -2, 1, 0, 0, -2, 1, 0, 0, 0, -2, 1, 0, 0, 0, 0, -2, 1, 0, 0, 0, 0, 0, -2, 1, 0, 0, 0, 0, 0, 0, -2, 1, 0, 0, 0, 0, 0, 0, 0, -2, 1, 0, 0, 0, 0, 0, 0, 0, 0, -2, 1 CROSSREFS Sequence in context: A144886 A117380 A185420 * A201639 A078939 A135891 Adjacent sequences: A167429 A167430 A167431 * A167433 A167434 A167435 KEYWORD easy,nonn,tabl AUTHOR Paul Barry, Nov 03 2009 STATUS approved

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Last modified August 7 21:19 EDT 2024. Contains 375017 sequences. (Running on oeis4.)