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 A087454 #31 Sep 08 2022 08:45:11
%S A087454 1,2,3,2,6,10,9,5,4,15,26,28,21,11,8,9,30,51,17,36,61,20,14,78,73,51,
%T A087454 26,54,82,105,32,22,69,14,75,126,131,41,28,29,90,163,96,145,99,83,88,
%U A087454 56,114,172,39,120,217,42,43,44,135,226,208,141,85,21,77,156,235,68,276
%N A087454 Multiplicative inverse of the n-th prime prime(n) modulo prime(n-1).
%H A087454 Charles R Greathouse IV, <a href="/A087454/b087454.txt">Table of n, a(n) for n = 2..10000</a>
%e A087454 We have a(7) = 10 because prime(7)*10 = 170 = 1 [mod 13] = 1 [mod prime(6)].
%p A087454 seq(`mod`(1/ithprime(n), ithprime(n-1)), n = 2..70); # _G. C. Greubel_, Aug 09 2019
%t A087454 Table[PowerMod[Prime[n], -1, Prime[n - 1]], {n, 2, 68}] (* _Geoffrey Critzer_, May 16 2015 *)
%o A087454 (PARI) a(n)=my(p=prime(n-1),g=nextprime(p+1)-p);lift(Mod(1/g,p)) \\ _Charles R Greathouse IV_, Aug 23 2011
%o A087454 (Magma) [InverseMod(NthPrime(n), NthPrime(n-1)): n in [2..70]]; // _G. C. Greubel_, Aug 09 2019
%o A087454 (Sage) [nth_prime(n).inverse_mod(nth_prime(n-1)) for n in (2..70)] # _G. C. Greubel_, Aug 09 2019
%Y A087454 Cf. A069830, A077005.
%K A087454 nonn,look
%O A087454 2,2
%A A087454 _Lekraj Beedassy_, Oct 23 2003
%E A087454 Corrected and extended by _Ray Chandler_, Oct 24 2003