243871

Properties

Appears in sequences

• a(n) is the number of indecomposable involutions of length n.at n=12A140456
• Let m = n-th number not divisible by 3 (A001651); a(n) = position of m in A065075, or -1 if never appears in A065075.at n=39A230289
• Prime numbersat n=21538