A178563 Primes p such that A178344(p) is also prime.

3, 11, 37, 47, 59, 131, 149, 151, 157, 163, 181, 191, 193, 197, 229, 233, 239, 251, 523, 541, 547, 557, 569, 599, 601, 613, 617, 631, 643, 653, 661, 677, 701, 727, 751, 761, 769, 787, 809, 823, 839, 883, 937, 941, 947, 953, 967, 971, 1021

Offset: 1

Author

Juri-Stepan Gerasimov, May 29 2010

Keywords

• nonn

Examples

			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.
		

Links

• Michael De Vlieger, Table of n, a(n) for n = 1..10000

Programs

Maple

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

Mathematica

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

Extensions

229, 233, 541 inserted by R. J. Mathar, Jun 07 2010