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A015490 a(0)=1, a(1)=5, a(n) = sum_{k=0}^{k=n-1} 5^k a(k). 0

%I

%S 1,5,26,676,85176,53320176,166678870176,2604524025370176,

%T 203481044006070370176,79484986295915244420370176,

%U 155244193344195757673779920370176,1516056730871105040228764708644920370176

%N a(0)=1, a(1)=5, a(n) = sum_{k=0}^{k=n-1} 5^k a(k).

%F a(n) = (5^(n-2) + 1) * a(n-1). - _Vincenzo Librandi_, Nov 11 2012

%o (Magma) I:=[1, 5, 26]; [n le 3 select I[n] else (5^(n-2)+1)*Self(n-1): n in [1..15]]; // _Vincenzo Librandi_, Nov 11 2012

%K nonn,easy

%O 0,2

%A _Olivier GĂ©rard_

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Last modified February 3 10:55 EST 2023. Contains 360034 sequences. (Running on oeis4.)