A271041 a(n) = k is the least squarefree number with a run of zero nonsquarefree numbers immediately preceding k and a run of exactly n>=0 nonsquarefree numbers immediately succeeding k.

2, 3, 7, 47, 8474, 843, 22019, 826823, 1092746, 33908367, 262315466

Offset: 0

Author

Hartmut F. W. Hoft, Mar 29 2016

Keywords

• nonn
• more

Comments

This is the top row (indexed by zero) of the doubly infinite matrix T(i,j) defined in A270996: a(n) = A270996((n+1)*(n+2)/2-1).

a(11) = T(0,11) > 3*10^9.

Examples

			a(3) = 47 since 46, 47 and 51 are squarefree while 48, 49 and 50 constitute the first nonsquarefree triple after a pair of squarefree numbers.
		

Crossrefs

Cf. A005117, A268330, A270344, A270996.

Programs

Mathematica

(* We use function a270996[] from A270996 *)
Map[a270996[{0, 1000000},{0, #}]&,Range[0,7]]
(* computes a(0)...a(7) *)