A327918 The 16 pure prime dates of each non-leap year of the form concatenate(month,day) with month and day also prime numbers.

23, 211, 223, 37, 311, 313, 317, 331, 53, 523, 73, 719, 113, 1117, 1123, 1129

Offset: 1

Author

Wolfdieter Lang, Oct 08 2019

Keywords

• nonn
• easy
• fini
• full

Comments

For the numbers for leap years see A327919.

Only the months February (2), March (3), May (5), July (7) and November (11) qualify. The qualifying prime days are for month m=2: 3, 5, 7, 11, 13, 17, 19, 23; for month m = 11: 3, 5, 7, 11, 13, 17, 19, 23, 29 and for months m = 3, 5, and 7: 3, 5, 7, 11, 13, 17, 19, 23, 29, 31.

The months m = 2, 3, 5, 7, 11 contribute 3, 5, 2, 2, 4 days, respectively, adding to 16.

Crossrefs

Cf. A165243 (first three terms), A165292 (first five terms), A165555 (first two terms), A167187 (first two terms), A327348 (m and d nonprime allowed), A327914 (with 0 before d = 1..9), A327919 (leap year), A327920 (pure prime dates of d.m form).