28676

Appears in sequences

• Numbers k such that sigma(k) = sigma(k+8).at n=28A015876
• Positions of 4-digit terms in the continued fraction for Pi (3 is at position 0).at n=23A048959
• Expansion of 1/(1 - x^2 - 2 x^3 + x^4).at n=34A122512
• Number of (n+2) X 6 0..1 arrays with every 3 X 3 subblock having three equal elements in a row horizontally, vertically, diagonally or antidiagonally exactly three ways, and new values 0..1 introduced in row major order.at n=19A204750
• Partial sums of A006950.at n=39A233969
• a(n) = Fibonacci(n+2) + n - 2.at n=20A255875
• Composite numbers n such that n'=(n+8)', where n' is the arithmetic derivative of n.at n=5A257105
• Indices of primes in A000712.at n=25A285217
• Indices of 0 in A348295: numbers m such that Sum_{k=1..m} (-1)^(floor(k*(sqrt(2)-1))) = Sum_{k=1..m} (-1)^A097508(k) = 0.at n=44A348299
• a(n) is the least number k such that the sequence of elements of the continued fraction of the harmonic mean of the divisors of k is palindromic with length n, or -1 if no such k exists.at n=8A349478
• Number of polyominoes of n cells with both diagonal symmetries, for which the 180-degree rotational symmetry has an axis that coincides with the center of a square, but without 90-degree rotational symmetry.at n=41A351159
• Expansion of (1/x) * Series_Reversion( x / (1-x) * (1-x-x^3)^2 ).at n=9A369489
• Expansion of e.g.f. exp((g^4 - 1)/4), where g = 1+x*g^2 is the g.f. of A000108.at n=5A391555