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A100690 a(n) = p * 5^p - 1 where p=prime(n). 1

%I #21 Sep 08 2022 08:45:15

%S 49,374,15624,546874,537109374,15869140624,12969970703124,

%T 362396240234374,274181365966796874,5401670932769775390624,

%U 144354999065399169921874,2692104317247867584228515624

%N a(n) = p * 5^p - 1 where p=prime(n).

%H Harvey P. Dale, <a href="/A100690/b100690.txt">Table of n, a(n) for n = 1..224</a>

%F a(n) = A064751(prime(n)) = A064751(A000040(n)). - _Michel Marcus_, Aug 27 2015

%e a(1) = 2*5^2 - 1 = 49.

%t Do[Print[Prime[n]*5^(Prime[n]) - 1], {n, 1, 20}] (* _Stefan Steinerberger_, Feb 15 2006 *)

%t #*5^#-1&/@Prime[Range[20]] (* _Harvey P. Dale_, Jun 12 2016 *)

%o (PARI) main(m)=forprime(p=2,m,print1(p * 5^p - 1,", ")) \\ _Anders Hellström_, Aug 27 2015

%o (Magma) [NthPrime(n) * 5^(NthPrime(n)) - 1: n in [1..20]]; // _Vincenzo Librandi_, Aug 27 2015

%K nonn

%O 1,1

%A _Parthasarathy Nambi_, Dec 07 2004

%E More terms from _Stefan Steinerberger_, Feb 15 2006

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Last modified March 29 09:59 EDT 2024. Contains 371268 sequences. (Running on oeis4.)