A196661 Expansion of g.f. (1-2*x)/(1-7*x).
1, 5, 35, 245, 1715, 12005, 84035, 588245, 4117715, 28824005, 201768035, 1412376245, 9886633715, 69206436005, 484445052035, 3391115364245, 23737807549715, 166164652848005, 1163152569936035, 8142067989552245, 56994475926865715, 398961331488060005
Offset: 0
Links
- Index entries for linear recurrences with constant coefficients, signature (7).
Programs
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PARI
a(n)=if(n,5*7^(n-1),1) \\ Charles R Greathouse IV, Nov 21 2011
Formula
a(0) = 1, a(n) = 5*7^(n-1) for n>0.
a(n) = Sum_{k=0..n} A193722(n,k)*2^k.
From Elmo R. Oliveira, Mar 18 2025: (Start)
E.g.f.: (5*exp(7*x) + 2)/7.
a(n) = 7*a(n-1). (End)