66644

Appears in sequences

• Number of alternating compositions, i.e., compositions with alternating increases and decreases, starting with either an increase or a decrease.at n=25A025047
• Numbers k such that the value pi(k), the number of primes <= k, can be obtained deleting some of the repeating adjacent digits of k.at n=31A113898
• n and pi(n) are both made of nontrivial runs of identical digits, where pi(n)=A000720(n).at n=2A116056
• Numbers k whose decimal representation ends with that of pi(k) (where pi denotes the prime counting function A000720).at n=17A306572
• Number of alternating compositions of n, including twins (x,x).at n=25A344604