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

1,1

Links

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

Example

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.

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 *)

Crossrefs

Sequence in context: A119211 A119235 A119233 * A069358 A108544 A095088

Adjacent sequences: A178560 A178561 A178562 * A178564 A178565 A178566

Keyword

nonn

Author

Juri-Stepan Gerasimov, May 29 2010

Extensions

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

Status

approved