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A364655
Circuit rank and corank of the n-Pell graph.
0
0, 0, 1, 7, 30, 106, 339, 1021, 2956, 8324, 22965, 62371, 167306, 444302, 1170151, 3060409, 7956824, 20581576, 53000873, 135952639, 347525686, 885612402, 2250586811, 5705067061, 14429119332, 36418383564, 91744440541, 230719450651, 579286267938, 1452310024726
OFFSET
0,4
LINKS
Eric Weisstein's World of Mathematics, Circuit Rank.
Eric Weisstein's World of Mathematics, Graph Co-Rank.
Eric Weisstein's World of Mathematics, Pell Graph.
FORMULA
a(n) = A000129(n)*(n/2 - 1) + 1.
a(n) = 5*a(n-1) - 6*a(n-2) - 2*a(n-3) + 3*a(n-4) + a(n-5).
G.f.: -x^2*(1+x)^2/((-1+x)*(-1+2*x+x^2)^2).
MATHEMATICA
Table[Fibonacci[n + 1, 2] (n/2 - 1) + 1, {n, 0, 20}]
CoefficientList[Series[-x^2 (1 + x)^2/((-1 + x) (-1 + 2 x + x^2)^2), {x, 0, 20}], x]
LinearRecurrence[{5, -6, -2, 3, 1}, {0, 0, 1, 7, 30}, 20]
CROSSREFS
Cf. A000129.
Sequence in context: A038798 A276289 A062455 * A368528 A085277 A375995
KEYWORD
nonn,easy
AUTHOR
Eric W. Weisstein, Jul 31 2023
STATUS
approved