A388282 - OEIS

%I #8 Sep 16 2025 22:23:11

%S 2,6,12,54,36,25,20,150,270,675,180,5625,100,3375,4500,33750,900,

%T 93750,500,421875,67500,84375,4500,21875,6250,421875,187500,31640625,

%U 22500,1225,28,294,6300,23625,6300,306250,140,118125,94500,826875,1260,765625,700,165375,44100,2953125,6300,9646875,26250,918750,3937500

%N a(n) = A276086(n) * A276086(sigma(n)-n), where A276086 is the primorial base exp-function, and sigma is the sum of divisors function.

%H Antti Karttunen, <a href="/A388282/b388282.txt">Table of n, a(n) for n = 1..11550</a>

%H <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a>.

%H <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>.

%F a(n) = A276086(n) * A379493(n).

%F a(n) >= A388031(n), with equivalence iff n is one of the terms A388280.

%o (PARI)

%o A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };

%o A388282(n) = (A276086(n)*A276086(sigma(n)-n));

%Y Cf. A000203, A001065, A276086, A379493, A388031, A388280, A388281.

%K nonn

%O 1,1

%A _Antti Karttunen_, Sep 16 2025