A082049 Least composite number greater than n-th composite number having greater smallest prime factor than that of n-th composite number.

9, 9, 9, 25, 15, 15, 15, 25, 21, 21, 21, 25, 25, 25, 49, 27, 35, 33, 33, 33, 35, 35, 49, 39, 39, 49, 45, 45, 45, 49, 49, 49, 121, 51, 55, 55, 55, 77, 57, 65, 63, 63, 63, 65, 65, 77, 69, 69, 77, 75, 75, 75, 77, 77, 121, 81, 81, 85, 85, 85, 91, 87, 91, 91, 91, 121, 93, 95, 95

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

A020639(a(n)) > A020639(A002808(n)).

A082048(A002808(n)) <= a(n).

Mathematica

seq[lim_] := Module[{c = Select[Range[lim], CompositeQ], p, s = {}, n, v}, p = FactorInteger[#][[1, 1]] & /@ c; n = Length[p]; Do[v = 0; Do[If[p[[j]] > p[[i]], v = c[[j]]; Break[]], {j, i + 1, n}]; If[v == 0, Break[], AppendTo[s, v]], {i, 1, n}]; s]; seq[125] (* Amiram Eldar, Mar 26 2025 *)

Crossrefs

Cf. A002808, A020639, A056608.

Sequence in context: A192984 A069602 A160761 * A282242 A389160 A389166

Adjacent sequences: A082046 A082047 A082048 * A082050 A082051 A082052

Keyword

nonn

Author

Reinhard Zumkeller, Apr 02 2003

Status

approved