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A096238 Number of n-digit base-5 deletable primes. 0
2, 6, 14, 32, 69, 156, 377, 855, 2072, 5131, 12922, 32619, 83945, 217305, 571560, 1517012, 4056107 (list; graph; refs; listen; history; text; internal format)
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. "Digit" means digit in base b.
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.
LINKS
MATHEMATICA
b = 5; a = {2}; d = {2, 3};
For[n = 2, n <= 8, n++,
p = Select[Range[b^(n - 1), b^n - 1], PrimeQ[#] &];
ct = 0;
For[i = 1, i <= Length[p], i++,
c = IntegerDigits[p[[i]], b];
For[j = 1, j <= n, j++,
t = Delete[c, j];
If[t[[1]] == 0, Continue[]];
If[MemberQ[d, FromDigits[t, b]], AppendTo[d, p[[i]]]; ct++;
Break[]]]];
AppendTo[a, ct]];
a (* Robert Price, Nov 12 2018 *)
CROSSREFS
Sequence in context: A217941 A346679 A232434 * A074878 A065495 A131352
KEYWORD
nonn,base,more
AUTHOR
Michael Kleber, Feb 28 2003
EXTENSIONS
12 more terms from Ryan Propper, Jul 19 2005
STATUS
approved

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Last modified March 29 02:23 EDT 2024. Contains 371264 sequences. (Running on oeis4.)