A104126 - OEIS

%I #15 Dec 12 2021 15:44:05

%S 8,81,15625,5764801,3138428376721,3937376385699289,

%T 14063084452067724991009,37589973457545958193355601,

%U 480250763996501976790165756943041

%N a(n) = prime(n)^(prime(n)+1).

%C Sum of reciprocals rapidly converges to 0.1374098524791901212366977116..

%C A182938(a(n)) = 0. [_Reinhard Zumkeller_, Feb 18 2012]

%H Reinhard Zumkeller, <a href="/A104126/b104126.txt">Table of n, a(n) for n = 1..75</a>

%t #^(#+1)&/@Prime[Range[10]] (* _Harvey P. Dale_, Dec 12 2021 *)

%o (PARI) ptopp1(n) = { local(x,y,z,sr=0); forprime(x=1,n, y=x^(x+1); z=(x+1)^x; sr+=1./y; print1(y","); ); print(); print(sr) }

%o (Haskell)

%o a104126 n = p ^ (p + 1) where p = a000040 n

%o -- _Reinhard Zumkeller_, Feb 18 2012

%Y Cf. A051674, A000040.

%K easy,nonn

%O 1,1

%A _Cino Hilliard_, Mar 06 2005

%E Offset corrected by _Reinhard Zumkeller_, Feb 18 2012