OFFSET
1,1
COMMENTS
At least one digit 2 is required. - Robert Israel, Jul 10 2018
A179025 is a proper subsequence. - Jianing Song, Jul 10 2018
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
MAPLE
Digs:= [0, 1, 2, 4, 6, 8, 9]:
f:= proc(n) local L, x;
L:= convert(n, base, 7);
if not member(2, L) then return NULL fi;
x:= add(Digs[L[i]+1]*10^(i-1), i=1..nops(L));
if isprime(x) then x fi
end proc:
map(f, [$1..2000]); # Robert Israel, Jul 10 2018
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Lekraj Beedassy, Jun 25 2010
EXTENSIONS
Corrected by Ray Chandler, Jul 13 2010
STATUS
approved