30855

Appears in sequences

• Consider iteration of the function f(x) = sigma(phi(x)) = A062402(x). Sequence lists the numbers k such that the trajectory of k returns to k.at n=34A096998
• Solution of the complementary equation a(n) = a(n-1) + a(n-2) + b(0) + b(1) + ... + b(n-1), where a(0) = 1, a(1) = 2, b(0) = 3, and (a(n)) and (b(n)) are increasing complementary sequences.at n=16A295053
• Numbers k such that k and k+1 are both phi-practical numbers (A260653).at n=33A330871
• Number of labeled 3-connected planar graphs with n edges.at n=6A343871
• Numbers k such that A070313(k) = 2^k - (2*k+1) is a prime number.at n=13A344781
• Number of integer compositions of n with exactly one part above the diagonal.at n=17A351983
• Irregular triangle read by rows where T(n,k) is the number of integer compositions of n with k excedances (parts above the diagonal), all zeros removed.at n=56A352524
• Smallest k for which a chain of linked rods of length 1, ..., k can be folded in half in exactly n dictinct ways.at n=36A390056