login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A178563 Primes p such that A178344(p) is also prime. 1

%I

%S 3,11,37,47,59,131,149,151,157,163,181,191,193,197,229,233,239,251,

%T 523,541,547,557,569,599,601,613,617,631,643,653,661,677,701,727,751,

%U 761,769,787,809,823,839,883,937,941,947,953,967,971,1021

%N Primes p such that A178344(p) is also prime.

%H Michael De Vlieger, <a href="/A178563/b178563.txt">Table of n, a(n) for n = 1..10000</a>

%e a(22)=601 because 29^1 + 23^0 + 19^0 + 17^1 + 13^0 + 11^1 + 7^1 + 5^0 + 3^0 + 2^1 = 71 is prime and 601 = 1001011001_2.

%p A178344 := proc(n) local bdgs; bdgs := convert(n,base,2) ; add( ithprime(i)^op(i,bdgs), i=1..nops(bdgs)) ; end proc:

%p for n from 1 to 2000 do if isprime(n) and isprime(A178344(n)) then printf("%d,",n) ; end if; end do: # _R. J. Mathar_, Jun 07 2010

%t Select[Prime@ Range@ 200, PrimeQ@ Total@ MapIndexed[Prime[First@ #2]^#1 &, Reverse@ IntegerDigits[#, 2]] &] (* _Michael De Vlieger_, Feb 19 2019 *)

%K nonn

%O 1,1

%A _Juri-Stepan Gerasimov_, May 29 2010

%E 229, 233, 541 inserted by _R. J. Mathar_, Jun 07 2010

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 27 13:13 EDT 2020. Contains 337380 sequences. (Running on oeis4.)