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A171238
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Given M = triangle A122196 as an infinite lower triangular matrix, this sequence is Lim_{n=1..inf.} M^n.
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11
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1, 2, 5, 8, 16, 24, 40, 56, 88, 120, 176, 232, 328, 424, 576, 728, 968, 1208, 1568, 1928, 2464, 3000, 3768, 4536, 5632, 6728, 8248, 9768, 11864, 13960, 16784, 19608, 23400, 27192, 32192, 37192, 43760, 50328, 58824, 67320, 78280, 89240, 103200, 117160
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OFFSET
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1,2
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COMMENTS
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A171238 also = polcoeff: (1,2,3,...)*(1,0,2,0,5,0,8,0,16,...).
Number of binary partitions of n into two kinds of parts. - Joerg Arndt, Feb 26 2015
Let the n-th convolution power of the sequence = B, with C = the aerated variant of B. It appears that B/C = the binomial sequence starting (1, 2n,...). Example: The sequence squared = (1, 4, 14, 36, 89, 192,...) = B; with C = (1, 0, 4, 0, 14, 0, 36,...). Then B/C = A000292: (1, 4, 10, 20, 35, 56,...). - Gary W. Adamson, Aug 15 2016
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LINKS
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Vincenzo Librandi, Table of n, a(n) for n = 1..1000
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FORMULA
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Given M = triangle A122196 as an infinite lower triangular matrix, this sequence is Lim_{n=1..inf.}, a left-shifted vector considered as a sequence.
From Wolfdieter Lang, Jul 15 2010: (Start)
O.g.f.: x*Q(x) with Q(x)*(1-x)^2 = Q(x^2), for the eigensequence M*Q = Q with the column o.g.f.s (x^(2*m))/(1-x)^2, m>=0, of M.
Recurrence for b(n):=a(n+1): b(n)=0 if n<0, b(0)=1; if n even then b(n) = b(n/2)+2*b(n-1)-b(n-2), else b(n) = 2*b(n-1)- b(n-2). (End)
G.f.: 1/((1-x)*(1-x^2)*(1-x^4)* ... *(1- x^(2^k))* ...)^2. - Robert G. Wilson v, May 11 2012
Convolution square of A018819. - Michael Somos, Mar 28 2014
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EXAMPLE
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G.f. = x + 2*x^2 + 5*x^3 + 8*x^4 + 16*x^5 + 24*x^6 + 40*x^7 + 56*x^8 + ...
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MATHEMATICA
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CoefficientList[ Series[ 1/ Product[1 - x^(2^i), {i, 0, 6}]^2, {x, 0, 60}], x] (* Robert G. Wilson v, May 11 2012 *)
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CROSSREFS
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Cf. A018819.
Cf. A000292
Sequence in context: A168470 A295998 A129299 * A096541 A226015 A328547
Adjacent sequences: A171235 A171236 A171237 * A171239 A171240 A171241
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KEYWORD
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nonn,easy
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AUTHOR
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Gary W. Adamson, Dec 05 2009
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EXTENSIONS
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More terms from Wolfdieter Lang, Jul 15 2010
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STATUS
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approved
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