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 A130599 Transformation of sequence 3^k by sandwiching it between 1's. 0
 1, 1, 1, 3, 1, 9, 1, 27, 1, 81, 1, 243, 1, 729, 1, 2187, 1, 6561, 1, 19683, 1, 59049, 1, 177147, 1, 531441, 1, 1594323, 1, 4782969, 1, 14348907, 1, 43046721, 1, 129140163, 1, 387420489, 1, 1162261467, 1, 3486784401, 1, 10460353203, 1, 31381059609, 1, 94143178827 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS Index entries for linear recurrences with constant coefficients, signature (0,4,0,-3). FORMULA From Chai Wah Wu, Jan 09 2021: (Start) a(n) = 4*a(n-2) - 3*a(n-4) for n > 3. G.f.: (-x^3 - 3*x^2 + x + 1)/(3*x^4 - 4*x^2 + 1). (End) CROSSREFS Cf. A000244. Sequence in context: A070894 A090261 A303552 * A157674 A063467 A223140 Adjacent sequences:  A130596 A130597 A130598 * A130600 A130601 A130602 KEYWORD nonn,less AUTHOR Paul Curtz, Jun 17 2007 STATUS approved

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Last modified January 24 07:45 EST 2021. Contains 340398 sequences. (Running on oeis4.)