42211

Appears in sequences

• n written efficiently in natural numbers base, i.e., in form ...wxyz where n = 1*z + 2*y + 3*x + 4*w + ... with z <= 1, y < 2, x < 3, w < 4, ...at n=36A055611
• Numbers k = p*q*r (p, q, r prime) congruent to 0 mod p+q+r.at n=37A160394
• a(n) = n*(2*n^2 + 5*n + 1)/2.at n=33A162254
• Concatenation of multiplicities of prime divisors of highly composite numbers A002182(n).at n=32A245500
• G.f.: 1/(1 + x/(1 + 2*x^2/(1 + 3*x^3/(1 + 4*x^4/(1 + 5*x^5/(1 + 6*x^6/(1 + ... ))))))), a continued fraction.at n=34A285409
• Odd squarefree composite numbers k, divisible by the sum of their prime factors, sopfr (A001414).at n=28A308643
• a(1) = 1 and thereafter a(n) = a(n-1) + j(n-1) where j(1) = 1 and then j(n) = j(n-1)-1 if a(n) is composite or j(n) = 2*j(n-1) if a(n) is prime.at n=45A382671