Number of nondecreasing arrangements of n numbers in -(n+1)..(n+1) with sum zero and not more than two numbers equal.
A188230
Number of nondecreasing arrangements of n numbers in -(n+1)..(n+1) with sum zero and not more than two numbers equal.
Terms
- a(0) =1a(1) =4a(2) =12a(3) =52a(4) =221a(5) =1019a(6) =4818a(7) =23522a(8) =117209a(9) =594789a(10) =3062414a(11) =15966168a(12) =84132345a(13) =447457816a(14) =2399177028a(15) =12956403904a(16) =70416558196a(17) =384897011042
External references
- oeis: A188230