OFFSET
1,2
COMMENTS
Partial sums of A037521.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..700
Mircea Merca, Inequalities and Identities Involving Sums of Integer Functions J. Integer Sequences, Vol. 14 (2011), Article 11.9.1.
Index entries for linear recurrences with constant coefficients, signature (5,-4,1,-5,4).
FORMULA
a(n) = round((8*4^n - 14*n - 13)/42).
a(n) = floor((8*4^n - 14*n - 8)/42).
a(n) = ceiling((8*4^n - 14*n - 18)/42).
a(n) = round((8*4^n - 14*n - 8)/42).
a(n) = a(n-3) + 3*4^(n-2) - 1, n > 3.
a(n) = 5*a(n-1) - 4*a(n-2) + a(n-3) - 5*a(n-4) + 4*a(n-5), n > 5.
G.f.: x^2*(2+x)/ ( (1-4*x)*(1+x+x^2)*(1-x)^2 ).
EXAMPLE
a(4) = 0 + 2 + 9 + 36 = 47.
MAPLE
A178710 := proc(n) add( floor(4^i/7), i=0..n) ; end proc:
MATHEMATICA
Accumulate[Floor[4^Range[30]/7]] (* or *) LinearRecurrence[{5, -4, 1, -5, 4}, {0, 2, 11, 47, 193}, 30] (* Harvey P. Dale, Aug 15 2015 *)
PROG
(Magma) [Round((8*4^n-14*n-13)/42): n in [1..30]]; // Vincenzo Librandi, Jun 21 2011
(PARI) vector(30, n, ((8*4^n-14*n-8)/42)\1) \\ G. C. Greubel, Jan 25 2019
(Sage) [floor((8*4^n-14*n-8)/42) for n in (1..30)] # G. C. Greubel, Jan 25 2019
CROSSREFS
KEYWORD
nonn,less
AUTHOR
Mircea Merca, Dec 26 2010
STATUS
approved