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.
%I A101789 #18 May 23 2024 04:28:28 %S A101789 7,23,47,167,263,359,383,479,503,719,839,863,887,983,1319,1367,1439, %T A101789 1487,1823,2039,2063,2207,2447,2879,2903,2999,3023,3119,3167,3623, %U A101789 3863,4007,4079,4127,4679,4703,4799,4919,5087,5399,5639,5807,5879,5927,6047 %N A101789 Safe primes of the form 8*k-1: primes of the form 8*k-1 such that 4*k-1 is also a prime. %H A101789 Harvey P. Dale, <a href="/A101789/b101789.txt">Table of n, a(n) for n = 1..10000</a> %e A101789 4*1-1 = 3 and 8*1-1 = 7 are primes, so the first term is 7. %t A101789 Select[Prime[Range[800]],Mod[#,8]==7&&PrimeQ[(#-1)/2]&] (* _Harvey P. Dale_, Jan 31 2012 *) %o A101789 (PARI) is(k) = (k % 8 == 7) && isprime(k) && isprime(k\2); \\ _Amiram Eldar_, May 23 2024 %Y A101789 Intersection of A005385 and A007522. %Y A101789 Cf. A002515. %K A101789 easy,nonn %O A101789 1,1 %A A101789 Douglas Stones (dssto1(AT)student.monash.edu.au), Dec 16 2004