204516

Appears in sequences

• Numbers n such that 275*2^n-1 is prime.at n=25A050896
• Start with a single pentagon; at n-th generation add a pentagon at each expandable vertex; a(n) is the sum of all label values at n-th generation. (See comment for construction rules.)at n=25A247619
• a(n) = k is a number such that A090086(k), the smallest pseudoprime to base k (not necessarily exceeding n), is the n-th Carmichael number.at n=3A293279