21607

Appears in sequences

• Consider sequence of fractions A066657/A066658 produced by ratios of terms in A066720; let m = smallest integer such that all fractions 1/n, 2/n, ..., (n-1)/n have appeared when we reach A066720(m) = k; sequence gives values of k; set a(n) = -1 if some fraction i/n never appears.at n=16A066848
• Denominator of Product_{ 2 <= p < 2*n } (2*n - p)/p.at n=32A084763
• Binary digits, representing the rows of triangle A141727, written in base 10.at n=7A141733
• 50k^2-20k-23 interleaved with 50k^2+30k+17 for k=>0.at n=42A217894
• Triangle read by rows: Number of oriented graphs on n nodes with k components.at n=49A281446
• a(1) = 50 and for any n > 0, a(n+1)^2 is the smallest square that begins with a(n).at n=37A309123
• Radicands of pure cubic number fields of type BETA and subtype M0.at n=24A363699