T(n,k) = Sum_{d|k} phi(d)*n^(k/d)/k, triangle read by rows, T(n,k) for n >= 1 and 1 <= k <= n.

Terms

a(0) =1a(1) =2a(2) =3a(3) =3a(4) =6a(5) =11a(6) =4a(7) =10a(8) =24a(9) =70a(10) =5a(11) =15a(12) =45a(13) =165a(14) =629a(15) =6a(16) =21a(17) =76a(18) =336a(19) =1560a(20) =7826a(21) =7a(22) =28a(23) =119a(24) =616a(25) =3367a(26) =19684a(27) =117655a(28) =8a(29) =36