cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A101795 Primes of the form 4*k-1 such that 8*k-1, 16*k-1 and 32*k-1 are also primes.

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%I A101795 #14 May 13 2024 02:14:52
%S A101795 179,359,2699,3539,12119,17159,27479,53639,57839,63419,71399,74699,
%T A101795 82499,87539,101399,107279,107699,112919,122099,122819,126839,127139,
%U A101795 133499,139439,166739,167759,229739,253679,254279,287219,296099
%N A101795 Primes of the form 4*k-1 such that 8*k-1, 16*k-1 and 32*k-1 are also primes.
%H A101795 Amiram Eldar, <a href="/A101795/b101795.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..1000 from Harvey P. Dale)
%F A101795 a(n) = 4*A101794(n) - 1. - _Amiram Eldar_, May 13 2024
%e A101795 4*45-1 = 179, 8*45-1 = 359, 16*45-1 = 719 and 32*45-1 = 1439 are primes, so 179 is a term.
%t A101795 Select[Table[4n-1,{n,75000}],AllTrue[(#+1)*{1,2,4,8}-1,PrimeQ]&] (* _Harvey P. Dale_, Apr 23 2019 *)
%o A101795 (PARI) is(k) = if(k % 4 == 3, my(m = k\4 + 1); isprime(4*m-1) && isprime(8*m-1) && isprime(16*m-1) && isprime(32*m-1), 0); \\ _Amiram Eldar_, May 13 2024
%Y A101795 Cf. A002515, A101794, A101796, A101797, A101798.
%Y A101795 Subsequence of A002145 and A101791.
%Y A101795 Subsequence: A101995.
%K A101795 easy,nonn
%O A101795 1,1
%A A101795 Douglas Stones (dssto1(AT)student.monash.edu.au), Dec 16 2004