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A227380 Doubling the first two of every four nonnegative numbers. 2
0, 2, 2, 3, 8, 10, 6, 7, 16, 18, 10, 11, 24, 26, 14, 15, 32, 34, 18, 19, 40, 42, 22, 23, 48, 50, 26, 27, 56, 58, 30, 31, 64, 66, 34, 35, 72, 74, 38, 39, 80, 82, 42, 43, 88, 90, 46, 47, 96, 98, 50, 51, 104, 106, 54, 55, 112, 114 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

a(n) and its differences:

0,    2,  2,   3,   8,  10,   6,   7,  16,...

2,    0,  1,   5,   2,  -4,   1,   9,   2,...

-2,   1,  4,  -3,  -6,   5,   8,  -7, -10,...   see A103889(n)

3,    3, -7,  -3,  11,   3, -15,  -3,  19,...

0,  -10,  4,  14,  -8, -18,  12,  22, -16,...

-10, 14, 10,- 22, -10,  30,  10, -38, -10,... .

The inverse binomial transform is

b(n)=0, 2, -2, 3, 0, -10, 24, -28, 0, 72, -160, 176, 0,...

    =(0, 1, -1, 1, 0, -1, 4, -4, 0, 4, -16, 16, 0,...) * a(n).

LINKS

Table of n, a(n) for n=0..57.

Index entries for linear recurrences with constant coefficients, signature (2,-3,4,-3,2,-1).

FORMULA

a(n) = n*A130658(n+2) = 2*A227316(n)/(n+1).

a(n) - a(n-4) = period 4:repeat 8, 8, 4, 4 = 4*A130658(n+2).

G.f.: (x^5 + 5*x^3 - 2*x^2 + 2*x)/((1-x)^2 * (1+x^2)^2. - Ralf Stephan, Jul 13 2013

CROSSREFS

Cf. A001477.

Sequence in context: A300354 A091681 A076541 * A159789 A153932 A158763

Adjacent sequences:  A227377 A227378 A227379 * A227381 A227382 A227383

KEYWORD

nonn

AUTHOR

Paul Curtz, Jul 09 2013

STATUS

approved

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Last modified July 5 18:40 EDT 2020. Contains 335473 sequences. (Running on oeis4.)