This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A073826 #23 Feb 20 2024 06:59:53
%S A073826 5,3413,50069,10405071317,
%T A073826 208492413443704093346554910065262730566475781
%N A073826 Primes of the form Sum_{k=1..n} k^k, i.e., primes in A001923.
%C A073826 a(3) = A001923(10) = 10405071317 and the 45-digit a(4) = A001923(30) have been certified prime with Primo. Any additional terms are too big to include here.
%C A073826 The next term would have over 20000 digits; see A073825 for more information and updates.
%F A073826 a(j) = A001923(A073825(j)) = sum_{k=1..A073825(j)} k^k.
%F A073826 Intersection of A001923 with A000040.
%e A073826 a(1) = 5 = 1^1 + 2^2 is the smallest prime of the form A001923(n) = sum_{k=1..n} k^k, namely for n = 2 = A073825(1).
%e A073826 a(2) = sum_{k=1..A073825(2)} k^k = 1^1 + 2^2 + 3^3 + 4^4 + 5^5 = 3413, a prime, so 3413 is in this sequence (A073825(2) = 5).
%t A073826 Select[s=0;Table[s+=n^n,{n,5!}],PrimeQ[ # ]&] (* _Vladimir Joseph Stephan Orlovsky_, May 30 2010 *)
%o A073826 (PARI) s=0; for(k=1,1320, s=s+k^k; if(isprime(s), print1(s,",")))
%Y A073826 Cf. A073825 (corresponding n), A001923 (sum_{k=1..n} k^k).
%Y A073826 Cf. A122166 (indices of primes in A062970 (sum_{k=0..n} k^k)).
%K A073826 nonn
%O A073826 1,1
%A A073826 _Rick L. Shepherd_, Aug 13 2002
%E A073826 Edited by _M. F. Hasler_, Mar 22 2008
%E A073826 Typo in comment corrected by _Jonathan Vos Post_, Mar 23 2008