Let L_1 = (1) and L_2 = (1, 2); for any n > 2, L_n is obtained by inserting one n between each pair of consecutive terms of L_{n-1} coprime to n; a(n) gives the number of n's in L_n.
A370857
Let L_1 = (1) and L_2 = (1, 2); for any n > 2, L_n is obtained by inserting one n between each pair of consecutive terms of L_{n-1} coprime to n; a(n) gives the number of n's in L_n.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =1a(6) =7a(7) =9a(8) =19a(9) =13a(10) =55a(11) =21a(12) =131a(13) =157a(14) =303a(15) =317a(16) =1039a(17) =393a(18) =2471a(19) =2505a(20) =5643a(21) =6145a(22) =19235a(23) =7413a(24) =40235a(25) =51905a(26) =110435a(27) =110683a(28) =359141a(29) =45877
External references
- oeis: A370857