69090840
domain: N
Appears in sequences
- a(n) = denominator of Bernoulli(2n)/(2n).at n=17A006953
- One half of A075178.at n=35A075179
- Denominators from e.g.f. 1/(1-exp(-x)) - 1/x.at n=35A075180
- n*A027642(n).at n=36A164869
- First bisection of A164869.at n=18A164877
- For odd n, a(n) = 2; for even n, a(n) = denominator of Bernoulli(n)/n; The number 2 alternating with the elements of A006953.at n=35A185633
- Numbers k >= 3 where a record value of log(phi(k))/log(lambda(k)) is reached, where phi is the Euler totient function (A000010) and lambda is the Carmichael lambda function (A002322).at n=15A328272
- Numbers with a record number of divisors that have the same value of the Euler totient function (A000010).at n=18A328857
- Indices k of records of low value in the ratios A319696(k)/A000005(k) between the number of distinct values of the Euler totient function applied to the divisors of k and the number of divisors of k.at n=27A328859
- Maximum value in n-th row of A330541.at n=37A330542
- a(n) is the smallest number with exactly n divisors that are Moran numbers, or -1 if no such number exists.at n=31A333457
- a(n) is the least number k such that A373531(k) = n, or -1 if no such k exists.at n=23A373532