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 A379961 #9 Jan 24 2025 11:59:25
%S A379961 1,4,6,7,13,35,212,2311,2316,2322,2329,2550,9241,30030,30037,32341,
%T A379961 32347,34662,60066,512850,1023367,223092876,223092877,223095199,
%U A379961 223097490,223097491,223122913,446185741,6469693260,6479392984
%N A379961 Numbers k such that A276086(k)-1 is a perfect power (A001597), where A276086 is the primorial base exp-function.
%H A379961 <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a>.
%e A379961 A276086(1) = 2, -1 = 1 = A001597(1), thus 1 is included.
%e A379961 A276086(2311) = 26, -1 = 25 = 5^2, thus 2311 is included.
%e A379961 A276086(1023367) = 328510, -1 = 328509 = 69^3, thus 1023367 is included.
%o A379961 (PARI)
%o A379961 A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
%o A379961 is_A379961(n) = { my(x=A276086(n)); (1==(x-1) || ispower(x-1)); };
%Y A379961 Setwise difference A379960 \ A379962.
%Y A379961 Cf. A001597, A276086.
%K A379961 nonn,more
%O A379961 1,2
%A A379961 _Antti Karttunen_, Jan 24 2025