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.

A060210 Largest prime factor of 1+smaller term of twin primes.

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%I A060210 #15 Jul 08 2018 19:56:07
%S A060210 2,3,3,3,5,7,5,3,17,3,23,5,5,3,11,19,5,5,47,13,29,7,3,11,29,19,5,103,
%T A060210 107,11,5,137,23,13,7,17,43,7,59,13,3,41,71,43,31,11,17,11,19,31,67,5,
%U A060210 139,283,41,149,13,313,23,13,37,13,347,29,11,71,17,373,7,11,13,397,17
%N A060210 Largest prime factor of 1+smaller term of twin primes.
%C A060210 Also: Largest prime factor of the average, or the sum, of twin prime pairs. - _M. F. Hasler_, Jan 03 2011
%H A060210 T. D. Noe, <a href="/A060210/b060210.txt">Table of n, a(n) for n = 1..10000</a>
%e A060210 101 is the 9th lesser twin, 102 = 2*3*17, and its max p factor is 17=a(9).
%t A060210 FactorInteger[1+#][[-1,1]]&/@Select[Partition[Prime[Range[500]],2,1], #[[2]]- #[[1]]==2&][[All,1]] (* _Harvey P. Dale_, Jan 16 2017 *)
%o A060210 (PARI) p=3; for(n=1,1e3, until(o+2==p,p=nextprime(2+o=p)); print1(vecmax(factor(p-1)[,1])","))  \\ _M. F. Hasler_, Jan 03 2011
%Y A060210 Cf. A001359, A001454, A002822, A059960, A027856.
%K A060210 nonn
%O A060210 1,1
%A A060210 _Labos Elemer_, Mar 20 2001