137438691328
domain: N
Appears in sequences
- a(n) = 2^(n-1)*( 2^n + (-1)^n ).at n=19A003665
- a(n) = 2^(n-1)*(2^n - 1), n >= 0.at n=19A006516
- Multiply-perfect numbers: n divides sigma(n).at n=24A007691
- Multiply perfect numbers that are also harmonic numbers but are not arithmetic numbers.at n=11A046986
- a(n) = 2^(p-1)*(2^p-1) where p is prime(n).at n=7A060286
- Numbers m such that the sum of the first k divisors of m is equal to m for some k.at n=22A064510
- Numbers n such that sigma(n) / n is prime.at n=14A065997
- 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=12A068195
- Numbers k such that sigma(k)/k, sigma_3(k)/k and sigma_5(k)/k are all integers.at n=15A076231
- Numbers k such that sigma(k)/k and sigma_3(k)/k are both integers.at n=18A076233
- 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=12A076234
- a(n) = 2^(4n+1) - 2^(2n).at n=9A079598
- Smallest triangular number with exactly n divisors, or 0 if no such number exists.at n=37A081978
- Triangular numbers whose sum of aliquot divisors is also a triangular number.at n=23A083675
- A bisection of A000396.at n=3A099057
- Array read by rows: row n lists n-th even superperfect number A061652(n), n-th Mersenne prime A000668(n) and n-th perfect number A000396(n).at n=20A138728
- a(n) = A136007(n)*(A136007(n)+1)/2.at n=6A152953
- Perfect numbers whose number of proper divisors is prime.at n=3A154895
- a(n) = 6*a(n-1) - 8*a(n-2) for n > 1, a(0)=1, a(1)=6.at n=18A171476
- a(n) = 6*a(n-1) - 8*a(n-2) for n > 1; a(0) = 6, a(1) = 28.at n=17A171496