

A188809


Rigidlydeletable primes under the rule that leading zeros are disallowed.


3



2, 3, 5, 7, 13, 17, 29, 31, 43, 47, 59, 67, 71, 79, 83, 97, 103, 107, 127, 157, 163, 269, 271, 359, 383, 439, 457, 463, 487, 509, 547, 569, 571, 607, 643, 659, 683, 701, 709, 751, 769, 863, 907, 929, 983, 1087, 1217, 1303, 1427, 1487, 2069, 2371, 2609, 2671
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OFFSET

1,1


COMMENTS

Rigidlydeletable primes are deletable primes where the choice of digit to delete is unique (all other choices give nonprime numbers).


LINKS



EXAMPLE

103 is a member since removing a digit will either give 03 which has a leading zero, or give one of the numbers 13 or 10. 2017 is not a member since removing a digit will either give 017 which has a leading zero, or give one of the numbers 217, 207, or 201, which are all composite.  Arkadiusz Wesolowski, Nov 27 2021


MATHEMATICA

lst1 = {}; Do[If[PrimeQ[n], p = n; Label[begin]; lst2 = {}; Do[i = IntegerDigits[p]; c = FromDigits@Drop[i, {d}]; If[Length[i]  1 == IntegerLength[c], AppendTo[lst2, c]], {d, IntegerLength@p}]; t = Select[lst2, PrimeQ[#] &]; If[Length[t] == 1, p = FromDigits[t]; Goto[begin]]; If[IntegerLength[p] == 1, AppendTo[lst1, n]]], {n, 2671}]; lst1 (* Arkadiusz Wesolowski, Feb 22 2013 *)


CROSSREFS



KEYWORD

nonn,base


AUTHOR



EXTENSIONS



STATUS

approved



