Numbers covering A000027: a(n) = (1, 1, 2, 5) * A011557(n).

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =10a(5) =10a(6) =20a(7) =50a(8) =100a(9) =100a(10) =200a(11) =500a(12) =1000a(13) =1000a(14) =2000a(15) =5000a(16) =10000a(17) =10000a(18) =20000a(19) =50000a(20) =100000a(21) =100000a(22) =200000a(23) =500000a(24) =1000000a(25) =1000000a(26) =2000000a(27) =5000000a(28) =10000000a(29) =10000000