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Search: id:A127389
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| 1, 1, 0, 1, 2, 4, 10, 23, 56, 138, 344, 870, 2220, 5716, 14828, 38717, 101682, 268416, 711810, 1895432, 5066030, 13586082, 36547534, 98593064, 266661162, 722953814, 1964358938, 5348367006, 14589803090, 39870312218, 109136843138
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OFFSET
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0,5
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FORMULA
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G.f. satisfies: A(x) = (1 + x*A(x)^2)*(1+x)/(1+x+2*x^2).
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PROGRAM
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(PARI) {a(n)=local(A=1+x+x*O(x^n)); for(i=0, n, A=(1 + x*A^2)*(1+x)/(1+x+2*x^2)); polcoeff(A, n)}
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CROSSREFS
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This is INVERTi transform of A086625 (appropriately shifted). I.e. INVERT([1, 1, 0, 1, 2, 4, 10, 23, 56, 138, 344, 870, 2220, 5716]) gives: 1, 2, 3, 6, 12, 26, 59, 138, 332, 814, 2028, 5118, ... (beginning of A086625)
Sequence in context: A018111 A094987 A137681 this_sequence A152173 A032171 A127713
Adjacent sequences: A127386 A127387 A127388 this_sequence A127390 A127391 A127392
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KEYWORD
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nonn
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AUTHOR
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Antti Karttunen (His-Firstname.His-Surname(AT)gmail.com), Jan 16 2007. Generating function, PARI-program and most of the terms supplied by Paul D. Hanna (pauldhanna(AT)juno.com), Jan 15 2007.
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