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A231968 Squarefree numbers (A005117) of the form p*q*r*s with prime factors p, q, r, s with q = 2*p + 1, r = 2*q + 1 and s = 2*r + 1. 3

%I

%S 2530,59455,4112125651,66487065301,1069364586601,4313828719351,

%T 146264252084551,252626415665851,3398860950259501,10045301361318901,

%U 110736954977078251

%N Squarefree numbers (A005117) of the form p*q*r*s with prime factors p, q, r, s with q = 2*p + 1, r = 2*q + 1 and s = 2*r + 1.

%e 4112125651 = 89*179*359*719; 179 = 2*89 + 1; 359 = 2*179 + 1, 719 = 2*359 + 1.

%Y Cf. A005117, A000040, A231967, A231969, A231966.

%K nonn

%O 1,1

%A _Jaroslav Krizek_, Nov 18 2013

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Last modified January 22 21:47 EST 2022. Contains 350504 sequences. (Running on oeis4.)