login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A276455 Primes of the form Sum_{k=1..n} k^(k-1). 0

%I #54 Apr 13 2020 15:34:00

%S 3,701,45269999

%N Primes of the form Sum_{k=1..n} k^(k-1).

%C Searched up to n = 5000.

%C a(4) has 38019 digits (1973212031 ... 7493445627) and corresponds to n=9553. - _Robert Price_, Sep 23 2016; [number of digits in a(4) corrected by _Jon E. Schoenfield_, Nov 06 2016]

%C No other primes corresponding to n < 80000. - _Robert Price_, Mar 17 2017

%H Sebastiao Antonio da Silva, <a href="https://primes.utm.edu/curios/page.php/9.html">Prime Curios: 9^8 + 8^7 + 7^6 + 6^5 + 5^4 + 4^3 + 3^2 + 2^1 + 1^0 is prime</a>

%e 3 is in the sequence because 3 is prime and 3 = 2^1 + 1^0.

%e 701 is in the sequence because 701 is prime and 701 = 5^4 + 4^3 + 3^2 + 2^1 + 1^0.

%e 45269999 is in the sequence because 45269999 is prime and 45269999 = 9^8 + 8^7 + 7^6 + 6^5 + 5^4 + 4^3 + 3^2 + 2^1 + 1^0.

%t Select[Accumulate[Table[n^(n-1),{n,100}]],PrimeQ] (* _Harvey P. Dale_, Apr 13 2020 *)

%o (Sage)

%o sum = 0

%o seq = []

%o max_n = 2500

%o for n in range(1, max_n+1):

%o sum += n^(n-1)

%o if is_prime(sum):

%o seq.append(n)

%o print(seq)

%Y Primes in A060946.

%K nonn,bref

%O 1,1

%A _Robert C. Lyons_, Sep 06 2016

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 28 14:38 EDT 2024. Contains 371254 sequences. (Running on oeis4.)