18830

Appears in sequences

• Weird numbers: abundant (A005101) but not pseudoperfect (A005835).at n=31A006037
• Unitary weird numbers: unitary abundant (A034683) but not unitary pseudoperfect (A293188).at n=28A064114
• a(n) = number of m such that A080737(m) <= 2n.at n=44A080740
• a(n) = n*(n+1)*(14*n-11)/6.at n=20A172076
• Numbers n such that n''' = n''+ 1 where n'' and n''' are respectively the second and the third arithmetic derivative of n.at n=7A189941
• Bi-unitary weird numbers: bi-unitary abundant numbers (A292982) that are not bi-unitary pseudoperfect (A292985).at n=33A292986
• Expansion of e.g.f. (sec(x) + tan(x))*exp(x)*BesselI(1,2*x)/x.at n=8A306836
• Infinitary weird numbers: infinitary abundant numbers (A129656) that are not infinitary pseudoperfect numbers (A306983).at n=34A306984
• Starting at n, a(n) is the number of times we move from a negative position to a spot we have already visited according to the following rules. On the k-th step (k=1,2,3,...) move a distance of k in the direction of zero. If the number landed on has been landed on before, move a distance of k away.at n=31A324683
• a(n) = Sum_{k=1..n} (A000330(n) mod k^2).at n=49A344711
• Nonexponential weird numbers: nonexponential abundant numbers (A348604) that are not equal to the sum of any subset of their nonexponential divisors.at n=25A348631
• (1+e)-weird numbers: (1+e)-abundant numbers k such that no subset of the aliquot (1+e)-divisors of k sums to k.at n=26A349285
• Weird untouchable numbers.at n=9A357326
• Triangle read by rows: T(n,k) is the k-th Lie-Betti number of the hypercube graph on 2^(n-1) vertices, n >= 1, k >= 0.at n=23A361014
• Triangle read by rows: T(n,k) is the k-th Lie-Betti number of the hypercube graph on 2^(n-1) vertices, n >= 1, k >= 0.at n=27A361014