A261255 Where MU-numbers (cf. A007335) occur in A003586 (3-smooth numbers).

2, 3, 5, 8, 10, 11, 15, 16, 20, 24, 25, 26, 31, 33, 38, 39, 44, 45, 47, 53, 54, 57, 61, 64, 70, 71, 72, 75, 80, 83, 87, 90, 92, 96, 101, 104, 105, 109, 113, 115, 119, 123, 125, 129, 134, 138, 140, 144, 145, 149, 151, 156, 161, 165, 166, 168, 173, 178, 180

Offset

1,1

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

Formula

A007335(n) = A003586(a(n)).

Example

.   n |   A007335(n)     | a(n) | A003586(a(n))
.  ---+------+-----------+------+--------------
.   1 |    2 |         2 |    2 |            2
.   2 |    3 |         3 |    3 |            3
.   3 |    6 |     2 * 3 |    5 |            6
.   4 |   12 |   2^2 * 3 |    8 |           12
.   5 |   18 |   2 * 3^2 |   10 |           18
.   6 |   24 |   2^3 * 3 |   11 |           24
.   7 |   48 |   2^4 * 3 |   15 |           48
.   8 |   54 |   2 * 3^3 |   16 |           54
.   9 |   96 |   2^5 * 3 |   20 |           96
.  10 |  162 |   2 * 3^4 |   24 |          162
.  11 |  192 |   2^6 * 3 |   25 |          192
.  12 |  216 | 2^3 * 3^3 |   26 |          216 .

Prog

(Haskell)
import Data.List (findIndex); import Data.Maybe (fromJust)
a261255 n = fromJust (findIndex (== a007335 n) a003586_list) + 1

Crossrefs

Cf. A007335, A003586.

Sequence in context: A222172 A326379 A099107 * A085833 A066896 A369064

Adjacent sequences: A261252 A261253 A261254 * A261256 A261257 A261258

Keyword

nonn

Author

Reinhard Zumkeller, Aug 13 2015

Status

approved