A099915 Expansion of g.f. (1+4*x)/((1-x)*(1-10*x)).
1, 15, 155, 1555, 15555, 155555, 1555555, 15555555, 155555555, 1555555555, 15555555555, 155555555555, 1555555555555, 15555555555555, 155555555555555, 1555555555555555, 15555555555555555, 155555555555555555, 1555555555555555555, 15555555555555555555, 155555555555555555555
Offset: 0
Links
- Index entries for linear recurrences with constant coefficients, signature (11,-10).
Programs
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Mathematica
LinearRecurrence[{11,-10},{1,15},20] (* or *) Accumulate[ CoefficientList[ Series[ (1+4x)/(1-10x),{x,0,20}],x]] (* Harvey P. Dale, Apr 23 2011 *) -
PARI
Vec((1+4*x)/(1-11*x+10*x^2) + O(x^21)) \\ Elmo R. Oliveira, May 02 2025
Formula
a(n) = (14*10^n - 5)/9.
a(n) = 11*a(n-1) - 10*a(n-2), a(0)=1, a(1)=15.
E.g.f.: exp(x)*(14*exp(9*x) - 5)/9. - Elmo R. Oliveira, May 02 2025
Extensions
More terms from Elmo R. Oliveira, May 02 2025
Comments