login
A176633
a(n) = 6*a(n-1)-8*a(n-2) for n > 2; a(0) = 83, a(1) = 708, a(2) = 2952.
5
83, 708, 2952, 12048, 48672, 195648, 784512, 3141888, 12575232, 50316288, 201295872, 805244928, 3221102592, 12884656128, 51539116032, 206157447168, 824631754752, 3298530951168, 13194131668992, 52776542404608
OFFSET
0,1
COMMENTS
Related to Reverse and Add trajectory of 77 in base 2: a(n) = A075253(4*n+1)/2, i.e., one half of second quadrisection of A075253.
FORMULA
a(n) = 6*(32*4^n-5*2^n) for n > 0, a(1) = 83.
G.f.: (83+210*x-632*x^2)/((1-2*x)*(1-4*x)).
G.f. for the sequence starting at a(1): 12*x*(59-108*x)/((1-2*x)*(1-4*x)).
MATHEMATICA
CoefficientList[Series[(83 + 210 x - 632 x^2)/((1 - 2 x) (1 - 4 x)), {x, 0, 40}], x] (* Vincenzo Librandi, Sep 24 2013 *)
LinearRecurrence[{6, -8}, {83, 708, 2952}, 30] (* Harvey P. Dale, Apr 08 2019 *)
PROG
(PARI) {m=20; v=concat([83, 708, 2952], vector(m-3)); for(n=4, m, v[n]=6*v[n-1]-8*v[n-2]); v}
(Magma) [83] cat [6*(32*4^n-5*2^n): n in [1..25]]; // Vincenzo Librandi, Sep 24 2013
CROSSREFS
Cf. A075253 (Reverse and Add trajectory of 77 in base 2), A176632, A176634, A176635, A171470.
Sequence in context: A142289 A164758 A142751 * A059236 A212379 A059935
KEYWORD
nonn
AUTHOR
Klaus Brockhaus, Apr 22 2010
STATUS
approved