Column 1 of triangle A277410.

Terms

a(0) =0a(1) =3a(2) =13a(3) =38a(4) =94a(5) =213a(6) =459a(7) =960a(8) =1972a(9) =4007a(10) =8089a(11) =16266a(12) =32634a(13) =65385a(14) =130903a(15) =261956a(16) =524080a(17) =1048347a(18) =2096901a(19) =4194030a(20) =8388310a(21) =16776893a(22) =33554083a(23) =67108488a(24) =134217324a(25) =268435023a(26) =536870449a(27) =1073741330a(28) =2147483122a(29) =4294966737