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A107733
Column 2 of the array in A107735.
1
1, 3, 13, 11, 141, 43, 1485, 171, 15565, 683, 163021, 2731, 1707213, 10923, 17878221, 43691, 187223245, 174763, 1960627405, 699051, 20531956941, 2796203, 215013444813, 11184811, 2251650026701, 44739243, 23579585203405, 178956971, 246928622013645, 715827883, 2585870100909261, 2863311531
OFFSET
3,2
COMMENTS
The second bisection [3, 11, 43, 171, 683, ...] is A007583. - Jean-François Alcover, Oct 22 2019 [noticed by Paul Curtz in a private e-mail].
REFERENCES
S. Mukai, An Introduction to Invariants and Moduli, Cambridge, 2003; see p. 483.
FORMULA
a(n) = 1 + Sum_{j=1..g} 2^(2j-1) if n = 2g+2, = 1 + 4 Sum_{j=1..g} C(2g+1, 2j) 5^(j-1) if n = 2g+1.
From Chai Wah Wu, Jun 19 2016: (Start)
a(n) = 17*a(n-2) - 80*a(n-4) + 128*a(n-6) - 64*a(n-8) for n > 10.
G.f.: x^3*(-64*x^7 + 96*x^5 - 40*x^3 - 4*x^2 + 3*x + 1)/(64*x^8 - 128*x^6 + 80*x^4 - 17*x^2 + 1). (End)
MATHEMATICA
LinearRecurrence[{0, 17, 0, -80, 0, 128, 0, -64}, {1, 3, 13, 11, 141, 43, 1485, 171}, 32] (* Jean-François Alcover, Oct 22 2019 *)
CROSSREFS
Sequence in context: A360967 A214811 A121565 * A273076 A272825 A054767
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jun 10 2005
EXTENSIONS
More terms from Emeric Deutsch, Jun 22 2005
STATUS
approved