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Numbers of the form p*2^(p-1) where p is prime.
4

%I #13 Sep 08 2022 08:46:20

%S 4,12,80,448,11264,53248,1114112,4980736,96468992,7784628224,

%T 33285996544,2542620639232,45079976738816,189115999977472,

%U 3307330976350208,238690780250636288,17005592192950992896,70328211781017665536,4943727411754159833088,83822005070936202543104

%N Numbers of the form p*2^(p-1) where p is prime.

%H G. C. Greubel, <a href="/A299795/b299795.txt">Table of n, a(n) for n = 1..460</a>

%F From _Michel Marcus_, Mar 07 2018: (Start)

%F a(n) = prime(n)*2^(prime(n)-1).

%F a(n) = A000040(n)*A061286(n).

%F a(n) = A001787(A000040(n)).

%F (End)

%p Primes := select(isprime, [$1..71]):

%p seq(p*2^(p-1), p in Primes);

%t Table[Prime[n]*2^(Prime[n] -1), {n,1,30}] (* _G. C. Greubel_, Mar 07 2018 *)

%o (PARI) a(n) = my(p = prime(n)); p*2^(p-1); \\ _Michel Marcus_, Mar 07 2018

%o (Magma) [NthPrime(n)*2^(NthPrime(n) -1): n in [1..30]]; // _G. C. Greubel_, Mar 07 2018

%Y A subsequence of A001787 and A300332.

%K nonn

%O 1,1

%A _Peter Luschny_, Mar 03 2018