33550336

Appears in sequences

• a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3), n > 3, with a(0)=a(1)=a(2)=0, a(3)=1.at n=27A000749
• a(n) = 2^(n-1)*( 2^n + (-1)^n ).at n=13A003665
• a(n) = 2^(n-1)*(2^n - 1), n >= 0.at n=13A006516
• Dual pairs of integrals arising from reflection coefficients.at n=26A007179
• Multiply-perfect numbers: n divides sigma(n).at n=12A007691
• Number of reversible strings with n beads of 2 colors. If more than 1 bead, not palindromic.at n=25A032085
• Harmonic seed numbers.at n=22A035527
• Sum of every 4th entry of row n in Pascal's triangle, starting at "n choose 0".at n=27A038503
• Number of elements of GF(2^n) with trace 0 and subtrace 0.at n=27A038518
• Number of elements of GF(2^n) with trace 1 and subtrace 1.at n=27A038521
• Multiply perfect numbers that are also harmonic numbers but are not arithmetic numbers.at n=4A046986
• Numbers k whose average divisor is nonintegral and divides k.at n=5A046999
• a(n) = 2^(p-1)*(2^p-1) where p is prime(n).at n=5A060286
• Numbers m such that the sum of the first k divisors of m is equal to m for some k.at n=13A064510
• Numbers n such that sigma(n) / n is prime.at n=7A065997
• Numbers of the form n(n+1)/2 whose only representation as a sum of 2 or more consecutive positive integers is 1+2+...+n.at n=9A068195
• Numbers n such that harmonic mean of the divisors of n is a prime.at n=16A074247
• Numbers k such that sigma(k)/k, sigma_3(k)/k and sigma_5(k)/k are all integers.at n=7A076231
• Numbers k such that sigma(k)/k and sigma_3(k)/k are both integers.at n=10A076233
• Numbers k such that sigma(k)/k, sigma_3(k)/k, sigma_5(k)/k and sigma_7(k)/k are all integers.at n=6A076234