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A322478 Primes that are not base-12 deletable primes (written in base 10). 1

%I #7 Dec 10 2018 02:40:46

%S 13,73,97,109,157,193,241,313,337,397,409,421,431,577,601,631,661,673,

%T 691,797,877,929,937,941,1009,1019,1021,1033,1063,1093,1103,1117,1123,

%U 1129,1151,1153,1201,1249,1297,1303,1307,1321,1381,1429,1439,1453,1489,1549,1597,1609,1619,1657,1693,1741

%N Primes that are not base-12 deletable primes (written in base 10).

%C 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.

%C 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.

%C Complement of all primes and A322477.

%H Robert Price, <a href="/A322478/b322478.txt">Table of n, a(n) for n = 1..319</a>

%t b = 12; d = {};

%t p = Select[Range[2, 10000], PrimeQ[#] &];

%t For[i = 1, i <= Length[p], i++,

%t c = IntegerDigits[p[[i]], b];

%t If[Length[c] == 1, AppendTo[d, p[[i]]]; Continue[]];

%t For[j = 1, j <= Length[c], j++,

%t t = Delete[c, j];

%t If[t[[1]] == 0, Continue[]];

%t If[MemberQ[d, FromDigits[t, b]], AppendTo[d, p[[i]]]; Break[]]]]; Complement[Table[Prime[n], {n, PrimePi[Last[d]]}], d] (* _Robert Price_, Dec 09 2018 *)

%Y Cf. A080608, A080603, A096235-A096246, A321657.

%K nonn,base,easy

%O 1,1

%A _Robert Price_, Dec 09 2018

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Last modified August 29 12:23 EDT 2024. Contains 375517 sequences. (Running on oeis4.)