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A282738
First differences of A282737.
2
1, 2, 1, 4, 1, 5, 1, 6, 1, 7, 1, 8, 1, 9, 1, 10, 1, 11, 1, 12, 1, 13, 1, 14, 1, 15, 1, 16, 1, 17, 1, 18, 1, 19, 1, 20, 1, 21, 1, 22, 1, 23, 1, 24, 1, 25, 1, 26, 1, 27, 1, 28, 1, 29, 1, 30, 1, 31, 1, 32, 1, 33, 1, 34, 1, 35, 1, 36, 1, 37, 1, 38, 1, 39, 1, 40, 1, 41, 1
OFFSET
0,2
FORMULA
G.f.: (1 + 2*x - x^2 - x^5) / (1 - x^2)^2.
From Colin Barker, Mar 04 2017: (Start)
a(n) = 2*a(n-2) - a(n-4) for n>3.
a(n) = 1 for n>1 and even.
a(n) = (n+5) / 2 for n>1 and odd.
(End)
PROG
(PARI) Vec((1 + 2*x - x^2 - x^5) / ((1 - x)^2*(1 + x)^2) + O(x^100)) \\ Colin Barker, Mar 04 2017
CROSSREFS
Cf. A282737.
A152271 and A133622 are very similar sequences.
Sequence in context: A284652 A261242 A088296 * A093890 A325609 A006306
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Mar 04 2017
STATUS
approved