Group the positive integers as (1, 2), (3, 4, 5), (6, 7, 8, 9, 10), (11, 12, 13, 14, 15, 16, 17), ... the n-th group containing prime(n) elements. Except the first, all groups contain an odd number of elements and hence have a middle term. Sequence gives the middle terms starting from group 2.
A073612
Group the positive integers as (1, 2), (3, 4, 5), (6, 7, 8, 9, 10), (11, 12, 13, 14, 15, 16, 17), ... the n-th group containing prime(n) elements. Except the first, all groups contain an odd number of elements and hence have a middle term. Sequence gives the middle terms starting from group 2.
Terms
- a(0) =4a(1) =8a(2) =14a(3) =23a(4) =35a(5) =50a(6) =68a(7) =89a(8) =115a(9) =145a(10) =179a(11) =218a(12) =260a(13) =305a(14) =355a(15) =411a(16) =471a(17) =535a(18) =604a(19) =676a(20) =752a(21) =833a(22) =919a(23) =1012a(24) =1111a(25) =1213a(26) =1318a(27) =1426a(28) =1537a(29) =1657
External references
- oeis: A073612