61739

Appears in sequences

• Number of certain stackings of n+1 squares on a double staircase.at n=19A055244
• a(n) is the least integer such that the iterated modulus chain m_1=mod(a(n),m),m_2=mod(a(n),m_1),m_3=mod(a(n),m_2),..., m_n= (0 or 1) reaches a length n. The companion value m, associated to a(n), is given in A177968.at n=32A177967
• Numerator of Sum_{k=1..n} 1/lambda(k), where lambda(k) is the Carmichael's lambda function.at n=38A211306
• a(n) = ceiling(n^3*(Pi/2)).at n=33A248198