Number of nondecreasing arrangements of n numbers x(i) in -(n+2)..(n+2) with the sum of sign(x(i))*2^|x(i)| zero.
A187983
Number of nondecreasing arrangements of n numbers x(i) in -(n+2)..(n+2) with the sum of sign(x(i))*2^|x(i)| zero.
Terms
- a(0) =0a(1) =4a(2) =9a(3) =30a(4) =111a(5) =355a(6) =1257a(7) =4357a(8) =15146a(9) =53379a(10) =187699a(11) =663631a(12) =2352610a(13) =8356208a(14) =29754352a(15) =106127185a(16) =379166226a(17) =1356700796a(18) =4860763378a(19) =17436188166a(20) =62613987171a(21) =225072940410a(22) =809789751003
External references
- oeis: A187983