8589869056

Appears in sequences

• a(n) = 2^(n-1)*( 2^n + (-1)^n ).at n=17A003665
• a(n) = 2^(n-1)*(2^n - 1), n >= 0.at n=17A006516
• Dual pairs of integrals arising from reflection coefficients.at n=34A007179
• Multiply-perfect numbers: n divides sigma(n).at n=18A007691
• Sum of every 4th entry of row n in Pascal's triangle, starting at "n choose 0".at n=35A038503
• Number of elements of GF(2^n) with trace 1 and subtrace 1.at n=35A038521
• Multiply perfect numbers that are also harmonic numbers but are not arithmetic numbers.at n=8A046986
• Numbers k whose average divisor is nonintegral and divides k.at n=16A046999
• a(n) = 2^(p-1)*(2^p-1) where p is prime(n).at n=6A060286
• Numbers m such that the sum of the first k divisors of m is equal to m for some k.at n=20A064510
• Numbers n such that sigma(n) / n is prime.at n=10A065997
• 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=11A068195
• Numbers k such that sigma(k)/k, sigma_3(k)/k and sigma_5(k)/k are all integers.at n=11A076231
• Numbers k such that sigma(k)/k and sigma_3(k)/k are both integers.at n=14A076233
• 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=9A076234
• a(n) = 2^(4n+1) - 2^(2n).at n=8A079598
• Smallest triangular number with exactly n divisors, or 0 if no such number exists.at n=33A081978
• Triangular numbers whose sum of aliquot divisors is also a triangular number.at n=20A083675
• a(n) = Sum_{k=0..n} binomial(4n+3,4k).at n=8A090408
• OU-Sigma multiperfect numbers.at n=24A091321