Number of nondecreasing arrangements of n numbers x(i) in -(n+1)..(n+1) with the sum of sign(x(i))*2^|x(i)| zero.
A187982
Number of nondecreasing arrangements of n numbers x(i) in -(n+1)..(n+1) with the sum of sign(x(i))*2^|x(i)| zero.
Terms
- a(0) =0a(1) =3a(2) =7a(3) =22a(4) =82a(5) =260a(6) =912a(7) =3158a(8) =10920a(9) =38385a(10) =134652a(11) =474953a(12) =1680801a(13) =5960094a(14) =21192029a(15) =75492493a(16) =269409262a(17) =963003740a(18) =3447075784a(19) =12354841859a(20) =44333177653a(21) =159250306113a(22) =572602762173
External references
- oeis: A187982