cp's OEIS Frontend

A214627 Primes in A161671.

%I A214627 #28 Mar 22 2022 18:53:28
%S A214627 2,3,7,19,29,43,47,71,83,101,113,193,197,229,241,271,283,293,311,347,
%T A214627 383,439,457,463,491,499,523,587,619,643,683,733,797,827,857,863,919,
%U A214627 991,1021,1031,1091,1151,1187,1289,1367,1549,1567,1619,1637,1693,1697,1733,1741,1811,1867,1871,1907
%N A214627 Primes in A161671.
%H A214627 Michael De Vlieger, <a href="/A214627/b214627.txt">Table of n, a(n) for n = 1..10000</a>
%H A214627 Michael De Vlieger, <a href="/A161671/a161671.png">Scatterplot of A161671(n)</a>, n = 1..120, showing and labeling primes p in this sequence in red and blue. The red primes are duplicated and are listed in A220220. We plot in green duplicated composite terms.
%F A214627 A161671 INTERSECT A000040.
%p A214627 isA214627 := proc(n)
%p A214627         if isprime(n) then
%p A214627                 for j from 1 do
%p A214627                         if A161671(j) = n then
%p A214627                                 return true;
%p A214627                         elif j >7 and A161671(j) > n then
%p A214627                                 return false;
%p A214627                         end if;
%p A214627                 end do:
%p A214627         else
%p A214627                 false;
%p A214627         end if;
%p A214627 end proc:
%p A214627 for n from 2 to 2000 do
%p A214627         if isA214627(n) then
%p A214627                 printf("%d,",n) ;
%p A214627         end if;
%p A214627 end do; # _R. J. Mathar_, Aug 09 2012
%t A214627 f[n_] := FixedPoint[n + PrimePi@ # &, n + PrimePi@ n]; Union@ Reap[Do[If[PrimeQ[#], Sow[#]] &[Prime[i] - f[i - 1] ], {i, 350}] ][[-1, -1]] (* _Michael De Vlieger_, Mar 22 2022, after _Robert G. Wilson v_ at A141468 *)
%Y A214627 Cf. A141468, A161671, A220220.
%K A214627 nonn
%O A214627 1,1
%A A214627 _Juri-Stepan Gerasimov_, Aug 08 2012