A159901 Concatenation of the first n squarefree numbers A005117.

1, 12, 123, 1235, 12356, 123567, 12356710, 1235671011, 123567101113, 12356710111314, 1235671011131415, 123567101113141517, 12356710111314151719, 1235671011131415171921, 123567101113141517192122

Offset

1,2

Links

Table of n, a(n) for n=1..15.

Formula

Prepend 1 to the terms of A159902(n-1).

Mathematica

With[{sn=Select[Range[30], SquareFreeQ]}, Table[FromDigits[Flatten[IntegerDigits/@ Take[ sn, n]]], {n, Length[sn]}]] (* Harvey P. Dale, Sep 03 2022 *)

Crossrefs

Cf. A005117.

Sequence in context: A187869 A362117 A262574 * A159900 A134802 A141266

Adjacent sequences: A159898 A159899 A159900 * A159902 A159903 A159904

Keyword

nonn,base,less

Author

Jaroslav Krizek, Apr 25 2009

Extensions

Slightly edited by R. J. Mathar, Apr 28 2009

Status

approved