OFFSET
1,1
COMMENTS
A prime p is a base-b deletable prime if when written in base b it has the property that removing some digit leaves either the empty string or another deletable prime. However, in base 2 we adopt the convention that 2 = 10 and 3 = 11 are deletable.
Deleting a digit cannot leave any leading zeros in the new string. For example, deleting the 2 in 2003 to obtain 003 is not allowed.
Complement of all primes and A096246.
LINKS
Robert Price, Table of n, a(n) for n = 1..2351
MATHEMATICA
d = {2, 3};
For[n = 3, n <= 15, n++,
p = Select[Range[2^(n - 1), 2^n - 1], PrimeQ[#] &];
For[i = 1, i <= Length[p], i++,
c = IntegerDigits[p[[i]], 2];
For[j = 1, j <= n, j++,
t = Delete[c, j];
If[t[[1]] == 0, Continue[]];
If[MemberQ[d, FromDigits[t, 2]], AppendTo[d, p[[i]]]; Break[]]]]]; Complement[Table[Prime[n], {n, PrimePi[Last[d]]}], d]
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Robert Price, Nov 14 2018
STATUS
approved