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 A271668 Triangle read by rows. The first column is A000217(n+1). From the second row we apply - A002262(n) for the following terms of the row. 1
 1, 3, 3, 6, 6, 5, 10, 10, 9, 7, 15, 15, 14, 12, 9, 21, 21, 20, 18, 15, 11, 28, 28, 27, 25, 22, 18, 13, 36, 36, 35, 33, 30, 26, 21, 15, 45, 45, 44, 42, 39, 35, 30, 24, 17, 55, 55, 54, 52, 49, 45, 40, 34, 27, 19, 66, 66, 65, 63, 60, 56, 51, 45, 38, 30, 21 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Row sums: A084990(n+1). A158405(n) = A002262(n) + A002260(n). See the formula. (Without its first column, A094728 is A120070, which could be built from positive A005563 and -A158894.) LINKS FORMULA a(n) = A094728(n+1) - A049780(n). EXAMPLE a(0) = 1, a(1) = 3, a(2) =3-0 = 3,  a(3) = 6, a(4) =6-0= 6, a(5) =6-1= 5, ... . Triangle: 1, 3,   3, 6,   6,  5, 10, 10,  9,  7, 15, 15, 14, 12,  9, 21, 21, 20, 18, 15, 11, 28, 28, 27, 25, 22, 18, 13, 36, 36, 35, 33, 30, 26, 21, 15, etc. MATHEMATICA Table[(n^2 - n)/2 - Prepend[Accumulate@ Range[0, n - 3], 0], {n, 12}] // Flatten (* Michael De Vlieger, Apr 12 2016 *) CROSSREFS Cf. A000096, A000217, A002260, A002262, A005408, A005563, A049780, A084990, A094728, A120070, A158405, A158894. Sequence in context: A307967 A131077 A175520 * A072464 A262871 A160745 Adjacent sequences:  A271665 A271666 A271667 * A271669 A271670 A271671 KEYWORD nonn,tabl AUTHOR Paul Curtz, Apr 12 2016 STATUS approved

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Last modified September 27 16:20 EDT 2020. Contains 337383 sequences. (Running on oeis4.)