

A188809


Rigidlydeletable primes.


2



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 composites).


LINKS

Arkadiusz Wesolowski, Table of n, a(n) for n = 1..10000
Chris Caldwell, The Prime Glossary, Deletable prime
Carlos Rivera, Puzzle 138


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

Cf. A080608 (deletable primes).
Sequence in context: A094947 A231474 A092621 * A152449 A048975 A009571
Adjacent sequences: A188806 A188807 A188808 * A188810 A188811 A188812


KEYWORD

base,nonn


AUTHOR

Arkadiusz Wesolowski, Apr 11 2011


STATUS

approved



