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Least common multiple of all p-1, where prime p divides the n-th primary pseudoperfect number A054377(n).
1

%I #16 Aug 18 2019 16:35:25

%S 1,2,6,42,330,235290,310800,1863851053628494074457830

%N Least common multiple of all p-1, where prime p divides the n-th primary pseudoperfect number A054377(n).

%C a(n) is a factor of any exponent k > 0 such that 1^k + 2^k + ... + p^k == 1 (mod p), where p = A054377(n).

%H J. Sondow and K. MacMillan, <a href="http://www.emis.de/journals/INTEGERS/papers/l34/l34.Abstract.html">Reducing the Erdős-Moser equation 1^n + 2^n + ... + k^n = (k+1)^n modulo k and k^2</a>, Integers 11 (2011), #A34.

%F a(n) = lcm(p-1 : prime p | A054377(n)).

%e A054377(3) = 42 = 2*3*7, so a(3) = lcm(2-1, 3-1, 7-1) = lcm(1,2,6) = 6.

%Y Cf. A054377.

%K nonn,more,hard

%O 1,2

%A _Kieren MacMillan_, Jun 20 2011