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 A132728 Triangle T(n, k) = 4 - 3*(-1)^k, read by rows. 2
 1, 1, 7, 1, 7, 1, 1, 7, 1, 7, 1, 7, 1, 7, 1, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS G. C. Greubel, Rows n = 0..30 of the triangle, flattened FORMULA From G. C. Greubel, Feb 14 2021: (Start) T(n, k) = 4 - 3*(-1)^k. Sum_{k=0..n} T(n, k) = (8*n + 5 - 3*(-1)^n)/2 = A047393(n+2). (End) Bivariate g.f.: (1 + 7*x*y)/((1 - x)*(1 - x*y)*(1 + x*y)). - J. Douglas Morrison, Jul 19 2021 EXAMPLE Triangle begins as:   1;   1, 7;   1, 7, 1;   1, 7, 1, 7;   1, 7, 1, 7, 1;   1, 7, 1, 7, 1, 7;   1, 7, 1, 7, 1, 7, 1;   1, 7, 1, 7, 1, 7, 1, 7;   1, 7, 1, 7, 1, 7, 1, 7, 1;   1, 7, 1, 7, 1, 7, 1, 7, 1, 7;   1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1; MATHEMATICA Table[PadRight[{}, n, {1, 7}], {n, 20}]//Flatten (* Harvey P. Dale, Aug 02 2019 *) Table[4 -3*(-1)^k, {n, 0, 12}, {k, 0, n}]//Flatten (* G. C. Greubel, Feb 14 2021 *) PROG (Sage) flatten([[4 -3*(-1)^k for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Feb 14 2021 (Magma) [4 -3*(-1)^k: k in [0..n], n in [0..12]]; // G. C. Greubel, Feb 14 2021 CROSSREFS Cf. A010688, A047393, A132742. Sequence in context: A322663 A231927 A199076 * A083530 A191562 A296472 Adjacent sequences:  A132725 A132726 A132727 * A132729 A132730 A132731 KEYWORD nonn,easy,tabl,less,changed AUTHOR Roger L. Bagula, Nov 17 2007 EXTENSIONS Edited and corrected by Joerg Arndt, Dec 26 2018 Offset and title changed by G. C. Greubel, Feb 14 2021 STATUS approved

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Last modified August 1 18:47 EDT 2021. Contains 346402 sequences. (Running on oeis4.)