Number of nondecreasing arrangements of n numbers x(i) in -(n+4)..(n+4) with the sum of sign(x(i))*2^|x(i)| zero.

A187985

Number of nondecreasing arrangements of n numbers x(i) in -(n+4)..(n+4) with the sum of sign(x(i))*2^|x(i)| zero.

Terms

    a(0) =0a(1) =6a(2) =13a(3) =49a(4) =181a(5) =597a(6) =2166a(7) =7592a(8) =26835a(9) =95590a(10) =339475a(11) =1211024a(12) =4324913a(13) =15465952a(14) =55398468a(15) =198646230a(16) =713134270a(17) =2562757415a(18) =9218114300a(19) =33185957425a(20) =119566240848a(21) =431102833455

External references