id:A123114 - OEIS Search Results

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a(n) = Sum_{r>0,s>0} binomial(r*s-1,n-1)/2^(r+s).

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1, 3, 13, 83, 701, 7363, 92541, 1354627, 22636861, 425241347, 8871085565, 203487078403, 5090418231549, 137920771272963, 4023549748488445, 125743894742698243, 4191213031967650813, 148414827031140706307 (list; graph; listen)

	OFFSET	`1,2`
	LINKS	`M. Maia and M. Mendez, On the arithmetic product of combinatorial species`
	FORMULA	`a(n) = 1/(n-1)!Sum_{k=1..n} Stirling1(n,k)b(k)^2, where b(n) = Sum_{k=1..n} (k-1)!*Stirling2(n,k).`
	CROSSREFS	`Cf. A101370, A000629.` `Sequence in context: A057993 A000904 A135743 this_sequence A104032 A130406 A152789` `Adjacent sequences: A123111 A123112 A123113 this_sequence A123115 A123116 A123117`
	KEYWORD	`easy,nonn`
	AUTHOR	`Vladeta Jovovic (vladeta(AT)eunet.rs), Sep 28 2006`

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Last modified December 10 12:37 EST 2009. Contains 170569 sequences.

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