A248745 Primes becoming a composite number if any digit is deleted (zeros allowed).

89, 227, 251, 257, 277, 281, 349, 409, 449, 499, 521, 557, 577, 587, 727, 757, 787, 821, 827, 857, 877, 881, 887, 991, 1117, 1129, 1171, 1187, 1259, 1289, 1423, 1447, 1453, 1471, 1483, 1543, 1553, 1559, 1583, 1621, 1669, 1721, 1741, 1747, 1777, 1847, 1889

Offset: 1

Author

Vladimir Shevelev, Oct 13 2014

Keywords

• nonn
• base

Comments

Since J. Gutierrez called terms of A051362 "super-prime numbers", then it is natural to call the terms of this sequence "weakest primes".

Links

• Peter J. C. Moses, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A051362, A000040.

Programs

Mathematica

compositeQ[n_]:=!(Abs[n]==1||PrimeQ[n]);
Select[Prime[Range[5,500]],Apply[And,Map[compositeQ[FromDigits[#]]&,Subsets[#,{Length[#]-1}]&[IntegerDigits[#]]]]&] (* Peter J. C. Moses, Oct 13 2014 *)
Select[Prime[Range[300]],AllTrue[FromDigits/@Table[Drop[IntegerDigits[#],{k}],{k,IntegerLength[#]}],CompositeQ]&] (* Harvey P. Dale, Oct 30 2021 *)

Extensions

More terms from Peter J. C. Moses, Oct 13 2014