A077721 Primes which can be expressed as sum of distinct powers of 7.

7, 2801, 17207, 19559, 120401, 134513, 134807, 137201, 840743, 842759, 842801, 941249, 943601, 958007, 958049, 958343, 960793, 5782001, 5784409, 5899307, 5899601, 5899657, 5901659, 6591089, 6607903, 6706393, 6708787, 6722801, 6722857, 6723193

Offset

1,1

Comments

Primes whose base 7 representation contains only zeros and 1's.

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

pos := 0:for i from 1 to 4000 do b := convert(i, base, 2); s := sum(b[j]*7^(j-1), j=1..nops(b)): if(isprime(s)) then pos := pos+1:a[pos] := s:fi: od:seq(a[j], j=1..pos);

Mathematica

Select[Prime[Range[10^6]], Max[IntegerDigits[#, 7]]<=1 &] (* Vincenzo Librandi, Sep 07 2018 *)

Crossrefs

Cf. A020449, A000695, A033044, A077717, A077718, A077719, A077720, A077722, A077723.

Sequence in context: A234621 A195680 A203587 * A235464 A297029 A242851

Adjacent sequences: A077718 A077719 A077720 * A077722 A077723 A077724

Keyword

nonn

Author

Amarnath Murthy, Nov 19 2002

Extensions

More terms from Sascha Kurz, Jan 03 2003

Status

approved