A304517 a(n) = 16*2^n - 11 (n>=1).
21, 53, 117, 245, 501, 1013, 2037, 4085, 8181, 16373, 32757, 65525, 131061, 262133, 524277, 1048565, 2097141, 4194293, 8388597, 16777205, 33554421, 67108853, 134217717, 268435445, 536870901, 1073741813, 2147483637, 4294967285, 8589934581, 17179869173, 34359738357, 68719476725, 137438953461, 274877906933, 549755813877
Offset: 1
Links
- Colin Barker, Table of n, a(n) for n = 1..1000
- A. Madanshekaf and M. Moradi, The first geometric-arithmetic index of some nanostar dendrimers, Iranian J. Math. Chemistry, 5, Supplement 1, 2014, s1-s6.
- Index entries for linear recurrences with constant coefficients, signature (3,-2).
Crossrefs
Programs
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GAP
List([1..40],n->16*2^n-11); # Muniru A Asiru, May 15 2018
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Maple
seq(16*2^n-11, n = 1 .. 40);
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Mathematica
Rest@ CoefficientList[Series[x (21 - 10 x)/((1 - x) (1 - 2 x)), {x, 0, 35}], x] (* or *) LinearRecurrence[{3, -2}, {21, 53}, 35] (* or *) Array[16*2^# - 11 &, 35] (* Michael De Vlieger, May 15 2018 *) -
PARI
Vec(x*(21 - 10*x) / ((1 - x)*(1 - 2*x)) + O(x^40)) \\ Colin Barker, May 15 2018
Formula
From Colin Barker, May 15 2018: (Start)
G.f.: x*(21 - 10*x) / ((1 - x)*(1 - 2*x)).
a(n) = 3*a(n-1) - 2*a(n-2) for n>2.
(End)
Comments