20923

Appears in sequences

• Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 15 ones.at n=25A031783
• Gaps of 6 in sequence A038593 (upper terms).at n=5A038652
• Numbers whose base-12 representation has exactly 5 runs.at n=28A043654
• Indices of primes in sequence defined by A(0) = 77, A(n) = 10*A(n-1) - 13 for n > 0.at n=13A056259
• Numerators of Newton-Cotes formulas.at n=30A093735
• Numerators of Newton-Cotes formulas.at n=31A093735
• Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 110-111-001 pattern in any orientation.at n=14A146236
• Positive numbers y such that y^2 is of the form x^2+(x+16807)^2 with integer x.at n=7A156713
• a(n) = floor((1 + 1/Pi)^n).at n=35A179492
• Number of 3X3X3 triangular 0..n arrays with no element lying outside the (possibly reversed) range delimited by its sw and se neighbors, and every horizontal row having the same average value.at n=21A214541
• Lengths of runs of the initial digits of semiprimes in decimal representation, cf. A239634.at n=41A239639
• a(1) = 1; a(n) = a(n-1) + 2 * a(floor(n/2)).at n=39A347027