Number of divisors of n of the form 5k+1; a(0)=0.

Terms

a(0) =0a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =2a(7) =1a(8) =1a(9) =1a(10) =1a(11) =2a(12) =2a(13) =1a(14) =1a(15) =1a(16) =2a(17) =1a(18) =2a(19) =1a(20) =1a(21) =2a(22) =2a(23) =1a(24) =2a(25) =1a(26) =2a(27) =1a(28) =1a(29) =1