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A177843 a(n) = 6*a(n-1)-8*a(n-2)-9 for n > 3; a(0)=775, a(1)=8919, a(2)=49581, a(3)=197469. 5
775, 8919, 49581, 197469, 788157, 3149181, 12589821, 50345469, 201354237, 805361661, 3221336061, 12885123069, 51540049917, 206159314941, 824635490301, 3298538422269, 13194146611197, 52776572289021, 211106260844541 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Related to Reverse and Add trajectory of 775 in base 2: a(n) = A077077(4*n), i.e. first quadrisection of A077077.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

FORMULA

a(n) = 3*4^(n+5)+27*2^(n+2)-3 for n > 1.

G.f.: (775+3494*x-2002*x^2-30932*x^3+28656*x^4) / ((1-x)*(1-2*x)*(1-4*x)).

G.f. for the sequence starting at a(2): 9*x^2*(5509-16622*x+11112*x^2) / ((1-x)*(1-2*x)*(1-4*x)).

MATHEMATICA

CoefficientList[Series[(775 + 3494 x - 2002 x^2 - 30932 x^3 + 28656 x^4)/((1 - x) (1 - 2 x) (1 - 4 x)), {x, 0, 40}], x] (* Vincenzo Librandi, Sep 24 2013 *)

PROG

(PARI) {m=19; v=concat([775, 8919, 49581, 197469], vector(m-4)); for(n=5, m, v[n]=6*v[n-1]-8*v[n-2]-9); v}

(MAGMA) [775, 8919] cat [3*4^(n+5)+27*2^(n+2)-3: n in [2..25]]; // Vincenzo Librandi, Sep 24 2013

CROSSREFS

Cf. A077077 (Reverse and Add trajectory of 775 in base 2), A177844, A177845, A177846.

Sequence in context: A252673 A077077 A177845 * A202893 A204300 A043519

Adjacent sequences:  A177840 A177841 A177842 * A177844 A177845 A177846

KEYWORD

nonn,easy

AUTHOR

Klaus Brockhaus, May 14 2010

STATUS

approved

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Last modified June 22 12:56 EDT 2021. Contains 345380 sequences. (Running on oeis4.)