Partial sums of A000419.

Terms

a(0) =3a(1) =9a(2) =20a(3) =32a(4) =46a(5) =65a(6) =86a(7) =108a(8) =132a(9) =159a(10) =189a(11) =222a(12) =257a(13) =295a(14) =337a(15) =380a(16) =424a(17) =470a(18) =518a(19) =569a(20) =623a(21) =679a(22) =736a(23) =795a(24) =857a(25) =923a(26) =990a(27) =1059a(28) =1129a(29) =1204