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A179024
Primes whose only prime digits are 2's.
2
2, 29, 211, 229, 241, 269, 281, 421, 821, 829, 929, 1021, 1129, 1201, 1229, 1249, 1289, 1291, 1429, 1621, 2011, 2029, 2069, 2081, 2089, 2099, 2111, 2129, 2141, 2161, 2221, 2269, 2281, 2411, 2441, 2609, 2621, 2689, 2699, 2801, 2819, 2861, 2909, 2969, 2999
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
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
Cf. A179025.
Sequence in context: A369384 A342454 A009772 * A179025 A377627 A244599
KEYWORD
nonn,base
AUTHOR
Lekraj Beedassy, Jun 25 2010
EXTENSIONS
Corrected by Ray Chandler, Jul 13 2010
STATUS
approved