A171521 Numbers that are not the product of k-th composite number and k for any k >= 1.

1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75

Offset

1,2

Comments

Complement of A071228.

Links

Table of n, a(n) for n=1..69.

Mathematica

Module[{nn=150, cmps}, cmps=Select[Range[nn], CompositeQ]; Complement[ Range[ Length[cmps]], Times@@@Thread[{cmps, Range[Length[cmps]]}]]] (* Harvey P. Dale, Jan 21 2023 *)

Crossrefs

Cf. A002808, A071228.

Sequence in context: A081023 A165332 A031179 * A352796 A092784 A047588

Adjacent sequences: A171518 A171519 A171520 * A171522 A171523 A171524

Keyword

nonn

Author

Jaroslav Krizek, Dec 11 2009

Extensions

More terms from Hugo Pfoertner, Jan 17 2022

Status

approved