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A340392 Primes of the form Sum_{k=i..j} k^k. 1

%I #11 Jan 06 2021 12:32:06

%S 5,31,283,3413,50069,17650823,10405071317,449317973725128511,

%T 18895749970915969007,18896062057839748031,846136323944176515589,

%U 40192544390028896900861,40192544398944997349117,40192544399240696440217,208492413443704093346554910065262730566475781

%N Primes of the form Sum_{k=i..j} k^k.

%H Robert Israel, <a href="/A340392/b340392.txt">Table of n, a(n) for n = 1..90</a>

%e a(1) = 5 = 1^1 + 2^2 is prime.

%e a(2) = 31 = 2^2 + 3^3 is prime.

%e a(3) = 283 = 3^3 + 4^4 is prime.

%e a(4) = 3413 = 1^1 + 2^2 + 3^3 + 4^4 + 5^5 is prime.

%e a(5) = 50069 = 1^1 + 2^2 + 3^3 + 4^4 + 5^5 + 6^6 is prime.

%e a(6) = 17650823 = 3^3 + 4^4 + 5^5 + 6^6 + 7^7 + 8^8 is prime.

%p B:= [0,seq(i^i,i=1..100)]:

%p S:= ListTools:-PartialSums(B):

%p R:=select(t -> t < 101^101 and isprime(t), {seq(seq(S[i]-S[j],j=1..i-1),i=2..101)}):

%p sort(convert(R,list));

%Y Cf. A073826.

%K nonn

%O 1,1

%A _J. M. Bergot_ and _Robert Israel_, Jan 05 2021

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Last modified April 19 08:20 EDT 2024. Contains 371782 sequences. (Running on oeis4.)