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A328189 Numbers n with at least one pair of consecutive divisible nontrivial divisors (greater than 1 and less than n). 11
8, 16, 18, 20, 27, 28, 32, 40, 42, 44, 50, 52, 54, 56, 64, 66, 68, 75, 76, 78, 80, 81, 88, 92, 98, 99, 100, 102, 104, 110, 112, 114, 116, 117, 124, 125, 126, 128, 130, 136, 138, 140, 147, 148, 152, 153, 156, 160, 162, 164, 170, 171, 172, 174, 176, 184, 186 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..57.

EXAMPLE

The nontrivial divisors of 42 are {2, 3, 6, 7, 14, 21}, with pairs of consecutive divisible divisors {3, 6} and {7, 14}, so 42 belongs to the sequence.

MATHEMATICA

Select[Range[200], MatchQ[DeleteCases[Divisors[#], 1|#], {___, x_, y_, ___}/; Divisible[y, x]]&]

CROSSREFS

Complement of A328161.

Positions of terms greater than 1 in A328194.

Partitions with a pair of consecutive divisible parts are A328221.

Cf. A000005, A060680, A060775, A067513, A088725, A163870, A328028, A328162, A328171.

Sequence in context: A004779 A247061 A180860 * A101766 A140270 A257225

Adjacent sequences:  A328186 A328187 A328188 * A328190 A328191 A328192

KEYWORD

nonn

AUTHOR

Gus Wiseman, Oct 13 2019

STATUS

approved

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Last modified February 20 14:14 EST 2020. Contains 332078 sequences. (Running on oeis4.)