id:A027881 - OEIS Search Results

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a(i)=a(i-1)+a(j_1)*a(j_2) {where j_1+j_2=i-1, j_1 <= q j_2} + a(j_1)*a(j_2)*a(j_3) {where j_1+j_2+j_3=i-1, j_1 <= q j_2 <= q j_3} +...+ a(1)^{i-1}.

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1, 1, 2, 4, 9, 20, 51, 121, 321, 826, 2186, 5789, 16114, 42449, 118281, 328425, 908933, 2510553, 7138324, 19869748 (list; graph; listen)

	OFFSET	`1,3`
	COMMENT	`At one time it was thought that this might be related to the Hopf algebra structure of perturbative Quantum Field Theory; this later proved not to be the case.`
	LINKS	`Dirk Kreimer, "On the Hopf algebra structure of perturbative quantum field theory"` `Dirk Kreimer, Home page`
	CROSSREFS	`Sequence in context: A006648 A128496 A134955 this_sequence A002861 A032200 A130969` `Adjacent sequences: A027878 A027879 A027880 this_sequence A027882 A027883 A027884`
	KEYWORD	`nonn`
	AUTHOR	`Dirk Kreimer (kreimer(AT)dipmza.physik.Uni-Mainz.DE)`

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.