A169903 Primitive primes in carryless arithmetic mod 10.

21, 23, 25, 27, 29, 51, 56, 201, 209, 227, 229, 241, 243, 261, 263, 287, 289, 551, 2023, 2027, 2043, 2047, 2061, 2069, 2081, 2089, 2207, 2209, 2221, 2223, 2263, 2267, 2281, 2287, 2401, 2407, 2421, 2423, 2441, 2449, 2483, 2489, 2603, 2609

Offset: 1

Author

David Applegate, Marc LeBrun and N. J. A. Sloane, Jul 11 2010

Keywords

• nonn
• base

Comments

Define the units in carryless arithmetic mod 10 to be the numbers 1, 3, 7 and 9 (these divide any number). A prime is a number N, not a unit, whose only factorizations are of the form N = u * M, where u is a unit.

A prime is primitive if it is not the carryless product of a smaller prime and a unit.

A subsequence of A169887.

Links

• David Applegate, Table of n, a(n) for n = 1..843 (all primitive primes with <= 6 digits)
• Index entries for sequences related to carryless arithmetic

Crossrefs

Cf. A004520, A059729, A168294, A168541, A169885, A169886, A169884, A169887.

Cf. A058943, A058945.