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 A209297 Triangle read by rows: T(n,k) = k*n + k - n, 1 <= k <= n. 9
 1, 1, 4, 1, 5, 9, 1, 6, 11, 16, 1, 7, 13, 19, 25, 1, 8, 15, 22, 29, 36, 1, 9, 17, 25, 33, 41, 49, 1, 10, 19, 28, 37, 46, 55, 64, 1, 11, 21, 31, 41, 51, 61, 71, 81, 1, 12, 23, 34, 45, 56, 67, 78, 89, 100, 1, 13, 25, 37, 49, 61, 73, 85, 97, 109, 121, 1, 14, 27 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Reinhard Zumkeller, Rows n = 1..120 of triangle, flattened FORMULA T(n,k) = (k-1)*(n+1)+1. EXAMPLE From Muniru A Asiru, Oct 31 2017: (Start) Triangle begins:   1;   1,  4;   1,  5,  9;   1,  6, 11, 16;   1,  7, 13, 19, 25;   1,  8, 15, 22, 29, 36;   1,  9, 17, 25, 33, 41, 49;   1, 10, 19, 28, 37, 46, 55, 64;   1, 11, 21, 31, 41, 51, 61, 71, 81;   1, 12, 23, 34, 45, 56, 67, 78, 89, 100;   ... (End) PROG (Haskell) a209297 n k = k * n + k - n a209297_row n = map (a209297 n) [1..n] a209297_tabl = map a209297_row [1..] (GAP) Flat(List([1..10^3], n -> List([1..n], k -> k * n + k - n))); # Muniru A Asiru, Oct 31 2017 CROSSREFS Cf. A162610; A000012 (left edge), A000290 (right edge), A006003 (row sums), A001844 (central terms), A026741 (number of odd terms per row), A142150 (number of even terms per row), A221490 (number of primes per row). Sequence in context: A016687 A139356 A318359 * A243525 A300071 A155060 Adjacent sequences:  A209294 A209295 A209296 * A209298 A209299 A209300 KEYWORD nonn,tabl AUTHOR Reinhard Zumkeller, Jan 19 2013 STATUS approved

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Last modified April 13 12:29 EDT 2021. Contains 342936 sequences. (Running on oeis4.)