The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A094068 Lessers of twin prime pairs whose greater has a prime prime index. 2

%I #16 Nov 30 2022 13:30:46

%S 3,29,107,239,281,857,1061,1151,1619,1667,1721,2267,2339,2801,2999,

%T 3167,3257,3467,3557,4271,4337,4547,4799,4931,5279,5501,5849,5867,

%U 6359,6659,6689,7349,8009,8219,8231,8387,9857,10007,10859,13001,13691,15269,15971

%N Lessers of twin prime pairs whose greater has a prime prime index.

%H Amiram Eldar, <a href="/A094068/b094068.txt">Table of n, a(n) for n = 1..10000</a>

%e 107 is the lesser of twin prime pair (107,109) the prime index of 109 (the greater) is 29.

%t seq = {}; p = prv = 2; k = 1; Do[p = NextPrime[p]; k++; If[p == prv + 2 && PrimeQ[k], AppendTo[seq, prv]]; prv = p, {10^3}]; seq

%t Select[Partition[Prime[Range[2000]],2,1],#[[2]]-#[[1]]==2&&PrimeQ[PrimePi[ #[[2]]]]&] [[All,1]] (* _Harvey P. Dale_, Nov 30 2022 *)

%o (PARI) lista(n) = {forprime(x=2,n, y=prime(x)- 2; if(isprime(y),print1(y",")))}

%Y Cf. A001097, A001359, A006512, A096479.

%K nonn

%O 1,1

%A _Cino Hilliard_, May 31 2004

%E Offset corrected by _Amiram Eldar_, Dec 27 2019

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 19 22:44 EDT 2024. Contains 372703 sequences. (Running on oeis4.)