43

This number is a prime.

Just showing those entries submitted by 'Beedassy': (Click here to show all)

The smallest nontrivial y for which the Pellian x² - 1847*y² = 1 is soluble. Note that 1847 is also prime. [Beedassy]

The number of distinct heptiamonds (i.e., triangular polyominoes with 7 cells), counted with reflections but not turning over. [Beedassy]

(There is one curio for this number that has not yet been approved by an editor.)