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 A154805 Numbers with 4n binary digits where every run length is 4, written in binary. 3
 1111, 11110000, 111100001111, 1111000011110000, 11110000111100001111, 111100001111000011110000, 1111000011110000111100001111, 11110000111100001111000011110000, 111100001111000011110000111100001111 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A154806 written in base 2. LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..100 Index entries for linear recurrences with constant coefficients, signature (10000,1,-10000). FORMULA From Colin Barker, Apr 20 2014: (Start) a(n) = (-10001-9999*(-1)^n+2^(5+4*n)*625^(1+n))/180018. a(n) = 10000*a(n-1)+a(n-2)-10000*a(n-3). G.f.: 1111*x / ((x-1)*(x+1)*(10000*x-1)). (End) EXAMPLE n ... a(n) ................... A154806(n) 1 ... 1111 ................... 15 2 ... 11110000 ............... 240 3 ... 111100001111 ........... 3855 4 ... 1111000011110000 ....... 61680 5 ... 11110000111100001111 ... 986895 MATHEMATICA CoefficientList[Series[1111/((x - 1) (x + 1) (10000 x - 1)), {x, 0, 10}], x] (* Vincenzo Librandi, Apr 22 2014 *) LinearRecurrence[{10000, 1, -10000}, {1111, 11110000, 111100001111}, 20] (* Harvey P. Dale, Jul 31 2017 *) PROG (PARI) Vec(1111*x/((x-1)*(x+1)*(10000*x-1)) + O(x^100)) \\ Colin Barker, Apr 20 2014 CROSSREFS Cf. A152775, A153435, A154806, A154807. Sequence in context: A291945 A015292 A274831 * A203897 A236050 A213979 Adjacent sequences:  A154802 A154803 A154804 * A154806 A154807 A154808 KEYWORD easy,nonn AUTHOR Omar E. Pol, Jan 25 2009 STATUS approved

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Last modified October 22 06:02 EDT 2018. Contains 316432 sequences. (Running on oeis4.)