cp's OEIS Frontend

A255578 Carmichael numbers of the form (12*k+1)*(24*k+1)*(36*k+1)*(72*k+1), where 12*k+1, 24*k+1, 36*k+1 and 72*k+1 are all primes.

%I A255578 #18 Sep 08 2022 08:46:11
%S A255578 461574735553,84154807001953,973694665856161,3060522900274753,
%T A255578 11861640972220321,386096840467598593,2322064552169233153,
%U A255578 7545246852649391713,9688364125836900193,10972742858243841313,11660828668219467073,16553878978808515681,17905475062325518273
%N A255578 Carmichael numbers of the form (12*k+1)*(24*k+1)*(36*k+1)*(72*k+1), where 12*k+1, 24*k+1, 36*k+1 and 72*k+1 are all primes.
%H A255578 Amiram Eldar, <a href="/A255578/b255578.txt">Table of n, a(n) for n = 1..10000</a>
%H A255578 Umberto Cerruti, <a href="/A255578/a255578.pdf">Pseudoprimi di Fermat e numeri di Carmichael</a> (in Italian), p. 14.
%o A255578 (Magma) [(12*n+1)*(24*n+1)*(36*n+1)*(72*n+1): n in [1..4000] | IsPrime(12*n+1) and IsPrime(24*n+1) and IsPrime(36*n+1) and IsPrime(72*n+1)];
%Y A255578 Cf. A002997, A255218.
%K A255578 nonn
%O A255578 1,1
%A A255578 _Vincenzo Librandi_, Feb 26 2015