login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A162610 Triangle read by rows in which row n lists n terms, starting with 2n-1, with gaps = n-1 between successive terms. 20
1, 3, 4, 5, 7, 9, 7, 10, 13, 16, 9, 13, 17, 21, 25, 11, 16, 21, 26, 31, 36, 13, 19, 25, 31, 37, 43, 49, 15, 22, 29, 36, 43, 50, 57, 64, 17, 25, 33, 41, 49, 57, 65, 73, 81, 19, 28, 37, 46, 55, 64, 73, 82, 91, 100, 21, 31, 41, 51, 61, 71, 81, 91, 101, 111, 121 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Note that the last term of the n-th row is the n-th square A000290(n).

Row sums are n*(n^2+2*n-1)/2, apparently in A127736. - R. J. Mathar, Jul 20 2009

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..10000

FORMULA

T(n,k) = n+k*n-k, 1<=k<=n. - R. J. Mathar, Oct 20 2009

T(n,k) = (k+1)*(n-1)+1. - Reinhard Zumkeller, Jan 19 2013

EXAMPLE

Triangle begins:

1

3, 4

5, 7, 9

7, 10, 13, 16

9, 13, 17, 21, 25

11, 16, 21, 26, 31, 36

MATHEMATICA

Flatten[Table[NestList[#+n-1&, 2n-1, n-1], {n, 15}]] (* Harvey P. Dale, Oct 20 2011 *)

PROG

From R. J. Mathar, Oct 20 2009: (Start)

(Python) def A162610(n, k):

...return 2*n-1+(k-1)*(n-1)

print([A162610(n, k) for n in range(1, 20) for k in range(1, n+1)])

(End)

(Haskell)

a162610 n k = k * n - k + n

a162610_row n = map (a162610 n) [1..n]

a162610_tabl = map a162610_row [1..]

-- Reinhard Zumkeller, Jan 19 2013

CROSSREFS

Cf. A000027, A000290, A159797, A159798.

Cf. A209297; A005408 (left edge), A000290 (right edge), A127736 (row sums), A056220 (central terms), A026741 (number of odd terms per row), A142150 (number of even terms per row), A221491 (number of primes per row).

Sequence in context: A174269 A112882 A180152 * A155935 A081606 A079945

Adjacent sequences:  A162607 A162608 A162609 * A162611 A162612 A162613

KEYWORD

easy,tabl,nonn

AUTHOR

Omar E. Pol, Jul 09 2009

EXTENSIONS

More terms from R. J. Mathar, Oct 20 2009

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 19 09:21 EDT 2018. Contains 316339 sequences. (Running on oeis4.)