A375234 Square array T(n,k), n>1 and k>1, read by antidiagonals in ascending order, giving the smallest n*k-digit number that, if arranged in an n X k matrix, forms a k-digit emirp (A006567) in each row and an n-digit emirp in each column, or -1 if no such number exists.

1331, 131337, 113337, 13139731, 113113337, 11933371, 1313717979, 113149971311, 119314713911, 1119737379, 131313131397, 113107709179991, 1193100990013911, 111971414339313, 111119333337

Offset

2,1

Links

Table of n, a(n) for n=2..16.

Example

T(3,2) = 131337 is the smallest 3*2-digit that if arranged in a 3 X 2 matrix yields in each row and column an emirp, i.e.,
 13
 13
 37
-> 13 (2 times), 37 (1 times), 113 (1 time), 337 (1 time) are all emirps.
Table begins (upper left corner = T(2,2)):
      1331       113337         11933371 ...
    131337    113113337     119314713911 ...
  13139731 113149971311 1193100990013911 ...
       ...          ...              ... ...

Crossrefs

Cf. A006567, A224164, A375171.

Sequence in context: A017655 A209844 A227475 * A036528 A052052 A122659

Adjacent sequences: A375231 A375232 A375233 * A375235 A375236 A375237

Keyword

nonn,base,tabl,more

Author

Jean-Marc Rebert, Aug 06 2024

Status

approved