Number of ordered pairs of distinct integer partitions of n.

Terms

a(0) =0a(1) =0a(2) =2a(3) =6a(4) =20a(5) =42a(6) =110a(7) =210a(8) =462a(9) =870a(10) =1722a(11) =3080a(12) =5852a(13) =10100a(14) =18090a(15) =30800a(16) =53130a(17) =87912a(18) =147840a(19) =239610a(20) =392502a(21) =626472a(22) =1003002a(23) =1573770a(24) =2479050a(25) =3831806a(26) =5931660a(27) =9057090a(28) =13819806a(29) =20834660