Number of n-element subsets that can be chosen from {1,2,...,2*n} having element sum n^2.
A202261
Number of n-element subsets that can be chosen from {1,2,...,2*n} having element sum n^2.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =3a(4) =7a(5) =18a(6) =51a(7) =155a(8) =486a(9) =1555a(10) =5095a(11) =17038a(12) =57801a(13) =198471a(14) =689039a(15) =2415043a(16) =8534022a(17) =30375188a(18) =108815273a(19) =392076629a(20) =1420064031a(21) =5167575997a(22) =18885299641a(23) =69287981666a(24) =255121926519a(25) =942474271999
External references
- oeis: A202261