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 A100688 #19 Sep 08 2022 08:45:15
%S A100688 17,80,1214,15308,1948616,20726198,2195382770,22082967872,
%T A100688 2165293113020,1990280943581606,19147875284802356,
%U A100688 16660504517966902430,1495392851464002242522,14115049597965094337960,1249674274871002654525988,1027312020387041054530226318
%N A100688 a(n) = prime(n) * 3^prime(n) - 1.
%e A100688 a(1) = 2*3^2 - 1 = 17.
%t A100688 Do[Print[Prime[n]*3^(Prime[n]) - 1], {n, 1, 20}] (* _Stefan Steinerberger_, Feb 15 2006 *)
%t A100688 # 3^#-1&/@Prime[Range[20]] (* _Harvey P. Dale_, Jan 24 2012 *)
%o A100688 (Magma) [NthPrime(n)*3^NthPrime(n) - 1: n in [1..20]]; // _Vincenzo Librandi_, Aug 27 2015
%Y A100688 Cf. A060352.
%K A100688 nonn
%O A100688 1,1
%A A100688 _Parthasarathy Nambi_, Dec 07 2004
%E A100688 More terms from _Stefan Steinerberger_, Feb 15 2006
%E A100688 a(15)-a(16) from _Vincenzo Librandi_, Aug 27 2015