A214627 - OEIS

%I #28 Mar 22 2022 18:53:28

%S 2,3,7,19,29,43,47,71,83,101,113,193,197,229,241,271,283,293,311,347,

%T 383,439,457,463,491,499,523,587,619,643,683,733,797,827,857,863,919,

%U 991,1021,1031,1091,1151,1187,1289,1367,1549,1567,1619,1637,1693,1697,1733,1741,1811,1867,1871,1907

%N Primes in A161671.

%H Michael De Vlieger, <a href="/A214627/b214627.txt">Table of n, a(n) for n = 1..10000</a>

%H 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 A161671 INTERSECT A000040.

%p isA214627 := proc(n)

%p         if isprime(n) then

%p                 for j from 1 do

%p                         if A161671(j) = n then

%p                                 return true;

%p                         elif j >7 and A161671(j) > n then

%p                                 return false;

%p                         end if;

%p                 end do:

%p         else

%p                 false;

%p         end if;

%p end proc:

%p for n from 2 to 2000 do

%p         if isA214627(n) then

%p                 printf("%d,",n) ;

%p         end if;

%p end do; # _R. J. Mathar_, Aug 09 2012

%t 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 Cf. A141468, A161671, A220220.

%K nonn

%O 1,1

%A _Juri-Stepan Gerasimov_, Aug 08 2012