A259366 Numbers for which the differences between consecutive divisors (ordered by size) are not distinct.

6, 12, 15, 18, 20, 24, 30, 36, 40, 42, 45, 48, 54, 56, 60, 63, 66, 70, 72, 75, 78, 80, 84, 90, 91, 96, 99, 100, 102, 105, 108, 110, 112, 114, 120, 126, 130, 132, 135, 138, 140, 144, 150, 156, 160, 162, 165, 168, 174, 180, 182, 186, 189, 192, 195, 198, 200

Offset

1,1

Comments

A060682(a(n)) < A000005(a(n)) - 1.

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Example

.    n |  A193829(n,*)      |  A027750(n,*)         |
.  ----+--------------------+-----------------------+------------
.   10 |  {1,3,5}           |  {1,2,5,10}           |
.   11 |  {10}              |  {1,11}               |
.   12 |  {1,1,1,2,6}       |  {1,2,3,4,6,12}       |  a(2) = 12
.   13 |  {12}              |  {1,13}               |
.   14 |  {1,5,7}           |  {1,2,7,14}           |
.   15 |  {2,2,10}          |  {1,3,5,15}           |  a(3) = 15
.   16 |  {1,2,4,8}         |  {1,2,4,8,16}         |
.   17 |  {16}              |  {1,17}               |
.   18 |  {1,1,3,3,9}       |  {1,2,3,6,9,18}       |  a(4) = 18
.   19 |  {18}              |  {1,19}               |
.   20 |  {1,2,1,5,10}      |  {1,2,4,5,10,20}      |  a(5) = 20
.   21 |  {2,4,14}          |  {1,3,7,21}           |
.   22 |  {1,9,11}          |  {1,2,11,22}          |
.   23 |  {22}              |  {1,23}               |
.   24 |  {1,1,1,2,2,4,12}  |  {1,2,3,4,6,8,12,24}  |  a(6) = 24
.   25 |  {4,20}            |  {1,5,25}             |            .

Prog

(Haskell)
a259366 n = a259366_list !! (n-1)
a259366_list = filter (\x -> a060682 x < a000005' x - 1) [2..]

Crossrefs

Cf. A193829, A027750, A060682, A000005, A060683 (complement), subsequence of A129512.

Sequence in context: A005279 A343281 A129512 * A196391 A343207 A362011

Adjacent sequences: A259363 A259364 A259365 * A259367 A259368 A259369

Keyword

nonn

Author

Reinhard Zumkeller, Jun 25 2015

Status

approved