A378697 Table T(n,k), 0 < n and 0 <= k < n, where the n-th row contains the smallest n-digit primes that remain prime even if any k of their digits are deleted, or -1 if no such prime exists.

2, 11, 23, 103, 113, 223, 2237, 10007, 10193, -1, 11113, 22273, 100003, 166931, -1, -1, 111119, 222323, 1000003, 1367777, -1, -1, -1, 1111711, 2222273, 10000019, 13334117, -1, -1, -1, -1, 11111117, 22222223, 100000007, 110499911, -1, -1, -1, -1, -1, 111111113, 222222227

Offset

1,1

Links

Table of n, a(n) for n=1..42.

Example

Row 2 contains 11 and 23 because 11 remains prime if any 0 of its digits are deleted, and 23 remains prime if any 1 of its digits is deleted, and no lesser 2-digit prime has this property.
Table begins:
  2;
  11, 23;
  103, 113, 223;
  1009, 1013, 1117, 2237;
  10007, 10193, -1, 11113, 22273;
  100003, 166931, -1, -1, 111119, 222323;
  1000003, 1367777, -1, -1, -1, 1111711, 2222273;
  10000019, 13334117, -1, -1, -1, -1, 11111117, 22222223;
  ...

Crossrefs

Cf. A003617, A019546, A051362, A378081, A378563.

Sequence in context: A218046 A342185 A217309 * A115374 A078699 A291679

Adjacent sequences: A378693 A378694 A378695 * A378699 A378700 A378701

Keyword

sign,base,tabl,new

Author

Jean-Marc Rebert, Dec 04 2024

Status

approved