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A304082 a(n) = 3^n - A006952(n). 2
0, 1, 1, 3, 3, 11, 9, 35, 33, 105, 105, 339, 313, 1035, 1017, 3115, 3099, 9579, 9345, 28947, 28713, 86979, 86825, 263187, 260865, 791577, 789497, 2376555, 2374521, 7150443, 7129401, 21471315, 21450489, 64431843, 64413177, 193487947, 193292811, 580650075 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Table of n, a(n) for n=0..37.

FORMULA

a(n) ~ 3^(n/2) / 2 if n is even and a(n) ~ 3^((n+1)/2) / 2 if n is odd.

a(n) ~ (1+sqrt(3) + (-1)^n*(1-sqrt(3))) * 3^(n/2) / 4.

MATHEMATICA

nmax = 60; 3^Range[0, nmax] - CoefficientList[Series[Product[(1 - x^k)/(1 - 3*x^k), {k, 1, nmax}], {x, 0, nmax}], x]

CROSSREFS

Cf. A006952, A264687.

Sequence in context: A107229 A302510 A164900 * A122167 A095019 A321082

Adjacent sequences:  A304079 A304080 A304081 * A304083 A304084 A304085

KEYWORD

nonn

AUTHOR

Vaclav Kotesovec, May 06 2018

STATUS

approved

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Last modified September 28 17:43 EDT 2020. Contains 337393 sequences. (Running on oeis4.)