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 A167428 #8 Feb 18 2019 11:11:43 %S A167428 3,3,11,11,11,17,17,17,29,29,29,29,29,29,29,29,41,41,41,41,41,41,41, %T A167428 41,59,59,59,59,59,59,59,59,59,59,59,59,59,71,71,71,71,71,71,71,71, %U A167428 101,101,101,101,101,101,101,101,101,101,101,101,101,101,101,101,101,101,101 %N A167428 Smallest non-isolated (or twin) prime > n-th non-isolated nonprime. %e A167428 a(1)=3 (>0); a(2)=3 (>1); a(3)=11 (>8); a(4)=11 (>8); a(5)=11 (>10); a(6)=17 (>14). %p A167428 A164276 := proc(n) option remember; if n = 1 then 0; else for a from procname(n-1)+1 do if isA164276(a) then return a; end if; end do; end if: end proc: %p A167428 isA164276 := proc(n) not isprime(n) and ( not isprime(n+1) or not isprime(n-1) ) ; end proc: %p A167428 isA001097 := proc(n) isprime(n) and ( isprime(n+2) or isprime(n-2) ); end proc: %p A167428 A167428 := proc(n) for a from A164276(n)+1 do if isA001097(a) then return a; end if; end do: end proc: %p A167428 seq(A167428(n),n=1..120) ; # _R. J. Mathar_, May 30 2010 %Y A167428 Cf. A001097, A164276. %K A167428 nonn %O A167428 1,1 %A A167428 _Juri-Stepan Gerasimov_, Nov 03 2009 %E A167428 Entries checked by _R. J. Mathar_, May 30 2010