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 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 (Python) # From R. J. Mathar, Oct 20 2009 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)]) (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

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Last modified August 10 07:37 EDT 2020. Contains 336368 sequences. (Running on oeis4.)