22413

Appears in sequences

• Numbers k such that phi(k) and sigma(k) are both perfect squares.at n=15A067781
• Q(n,6), where Q(m,k) is defined in A127080 and A127137.at n=37A127148
• Composite numbers, not ending with 0, sharing a 3-digit sequence with some of its prime factors.at n=23A131523
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, 0, 1), (-1, 1, 0), (0, 0, 1), (1, -1, 0), (1, 0, -1)}.at n=10A148324
• Number of compound perfect squared squares of order n up to symmetries of the square and its squared subrectangles.at n=32A181340
• Fibonacci sequence beginning 13, 6.at n=17A206612
• Number of length 2+2 0..n arrays with some pair in every consecutive three terms totalling exactly n.at n=25A245871
• Numbers n such that both phi(n) and psi(n) are perfect squares.at n=33A291549
• Numerator of variance of first n primes.at n=15A301275
• Numbers n such that phi(n), psi(n) and sigma(n) are simultaneously perfect squares.at n=7A301867
• Indices i where a run of nonzero values starts in A305671.at n=28A305672
• G.f.: 1/(1-x)^4 * Product_{k>=1} (1 + x^k).at n=18A325952