A260987 Record values in A008480.

1, 2, 3, 4, 6, 12, 20, 30, 60, 105, 120, 140, 180, 210, 280, 420, 504, 840, 1120, 1512, 1680, 2520, 3780, 5040, 6300, 7560, 9240, 12600, 13860, 15120, 15840, 27720, 34650, 37800, 55440, 83160, 102960, 110880, 138600, 180180, 205920, 216216, 240240, 332640

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..2011 (terms 1..80 from Reinhard Zumkeller)

Formula

a(n) = A008480(A260633(n)).

Example

.   n | x = A260633(n)        | y = a(n)             | [x/y] | x mod y
. ----+-----------------------+----------------------+-------+---------
.   1 |     1 | 1             |    1 | 1             |    1  |      0
.   2 |     6 | 2*3           |    2 | 2             |    3  |      0
.   3 |    12 | 2^2*3         |    3 | 3             |    4  |      0
.   4 |    24 | 2^3*3         |    4 | 2^2           |    6  |      0
.   5 |    30 | 2*3*5         |    6 | 2*3           |    5  |      0
.   6 |    60 | 2^2*3*5       |   12 | 2^2*3         |    5  |      0
.   7 |   120 | 2^3*3*5       |   20 | 2^2*5         |    6  |      0
.   8 |   180 | 2^2*3^2*5     |   30 | 2*3*5         |    6  |      0
.   9 |   360 | 2^3*3^2*5     |   60 | 2^2*3*5       |    6  |      0
.  10 |   720 | 2^4*3^2*5     |  105 | 3*5*7         |    6  |     90
.  11 |   840 | 2^3*3*5*7     |  120 | 2^3*3*5       |    7  |      0
.  12 |  1080 | 2^3*3^3*5     |  140 | 2^2*5*7       |    7  |    100
.  13 |  1260 | 2^2*3^2*5*7   |  180 | 2^2*3^2*5     |    7  |      0
.  14 |  1680 | 2^4*3*5*7     |  210 | 2*3*5*7       |    8  |      0
.  15 |  2160 | 2^4*3^3*5     |  280 | 2^3*5*7       |    7  |    200
.  16 |  2520 | 2^3*3^2*5*7   |  420 | 2^2*3*5*7     |    6  |      0
.  17 |  4320 | 2^5*3^3*5     |  504 | 2^3*3^2*7     |    8  |    288
.  18 |  5040 | 2^4*3^2*5*7   |  840 | 2^3*3*5*7     |    6  |      0
.  19 |  7560 | 2^3*3^3*5*7   | 1120 | 2^5*5*7       |    6  |    840
.  20 | 10080 | 2^5*3^2*5*7   | 1512 | 2^3*3^3*7     |    6  |   1008
.  21 | 12600 | 2^3*3^2*5^2*7 | 1680 | 2^4*3*5*7     |    7  |    840
.  22 | 15120 | 2^4*3^3*5*7   | 2520 | 2^3*3^2*5*7   |    6  |      0
.  23 | 25200 | 2^4*3^2*5^2*7 | 3780 | 2^2*3^3*5*7   |    6  |   2520
.  24 | 30240 | 2^5*3^3*5*7   | 5040 | 2^4*3^2*5*7   |    6  |      0
.  25 | 45360 | 2^4*3^4*5*7   | 6300 | 2^2*3^2*5^2*7 |    7  |   1260 .

Prog

(Haskell)
a260987 n = a260987_list !! (n-1)
(a260987_list, a260633_list) = unzip $ f 1 0 where
   f x r = if y > r then (y, x) : f (x + 1) y else f (x + 1) r
           where y = a008480 x

Crossrefs

Cf. A008480, A260633.

Sequence in context: A221846 A018343 A242459 * A102462 A277408 A018369

Adjacent sequences: A260984 A260985 A260986 * A260988 A260989 A260990

Keyword

nonn

Author

Reinhard Zumkeller, Nov 18 2015

Status

approved