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 A064217 #7 May 01 2022 13:19:59
%S A064217 4,6,18,24,138,60,150,720,150,234,138,966,138,420,60,1584,420,60,1830,
%T A064217 1134,162,1080,1482,684,240,10074,3378,3300,2742,984,2400,4050,5262,
%U A064217 3510,3378,960,3612,516,6840,6474,4680,4950,12612,7986,4290,8046,5208
%N A064217 Least k such that k*7^n +/- 1 are twin primes.
%t A064217 Do[ k = 1; While[ ! PrimeQ[ k*7^n + 1 ] || ! PrimeQ[ k*7^n - 1 ], k++ ]; Print[ k ], {n, 0, 50} ]
%Y A064217 Cf. A063983, A064213, A064214, A064215, A064218, A064220, A064221.
%K A064217 nonn
%O A064217 0,1
%A A064217 _Robert G. Wilson v_, Sep 21 2001
%E A064217 Offset corrected by _Georg Fischer_, May 01 2022