23718

Appears in sequences

• Number of nonempty subsets of {1, 2, ..., n} with <=5 pairwise coprime elements.at n=34A187266
• Number of (n+1) X 2 0..2 matrices with each 2 X 2 subblock idempotent.at n=15A224669
• Numbers x such that the base 10 representation of x^2 forms an arithmetic sequence when split into equal-sized chunks.at n=7A244660
• a(n) is the smallest number whose Collatz ('3x+1') trajectory crosses its initial value exactly n times.at n=54A301937
• Index of first occurrence of n in A349325.at n=26A350278