login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A245717 Triangle read by rows: T(n,k) = gcd(n,k^2), 1 <= k <= n. 3
1, 1, 2, 1, 1, 3, 1, 4, 1, 4, 1, 1, 1, 1, 5, 1, 2, 3, 2, 1, 6, 1, 1, 1, 1, 1, 1, 7, 1, 4, 1, 8, 1, 4, 1, 8, 1, 1, 9, 1, 1, 9, 1, 1, 9, 1, 2, 1, 2, 5, 2, 1, 2, 1, 10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 4, 3, 4, 1, 12, 1, 4, 3, 4, 1, 12, 1, 1, 1, 1, 1, 1, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Reinhard Zumkeller, Rows n = 1..125 of triangle, flattened

EXAMPLE

First rows and their sums (A078430):

.    1:   1                                           1

.    2:   1, 2                                        3

.    3:   1, 1, 3                                     5

.    4:   1, 4, 1, 4                                 10

.    5:   1, 1, 1, 1, 5                               9

.    6:   1, 2, 3, 2, 1,  6                          15

.    7:   1, 1, 1, 1, 1,  1, 7                       13

.    8:   1, 4, 1, 8, 1,  4, 1, 8                    28

.    9:   1, 1, 9, 1, 1,  9, 1, 1, 9                 33

.   10:   1, 2, 1, 2, 5,  2, 1, 2, 1, 10             27

.   11:   1, 1, 1, 1, 1,  1, 1, 1, 1,  1, 11         21

.   12:   1, 4, 3, 4, 1, 12, 1, 4, 3,  4,  1, 12     50

PROG

(Haskell)

a245717 n k = a245717_tabl !! (n-1) !! (k-1)

a245717_row n = a245717_tabl !! (n-1)

a245717_tabl = zipWith (zipWith gcd) a002024_tabl a133819_tabl

CROSSREFS

Cf. A050873, A002024, A133819, A078430 (row sums).

Sequence in context: A320250 A089141 A336084 * A248008 A327981 A277606

Adjacent sequences:  A245714 A245715 A245716 * A245718 A245719 A245720

KEYWORD

nonn,tabl

AUTHOR

Reinhard Zumkeller, Jul 30 2014

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 20 10:18 EST 2022. Contains 350471 sequences. (Running on oeis4.)