64665

Appears in sequences

• Numbers k such that k and k+1 have same sum of divisors.at n=18A002961
• Numbers k such that k and k+1 have the same number and sum of divisors.at n=6A054004
• Numbers k such that A065608(k) = A065608(k+1).at n=9A065062
• The Wiener index of the meta-polyphenyl chain with n hexagons (see the Dou et al. and the Deng references).at n=14A216110
• Numbers n such that sigma(n+1) - sigma(n) = k*n for some integer k, where sigma(n) = A000203 (sum of divisors of n).at n=26A223136
• Table of consecutive numbers with the same sum of divisors.at n=36A225757
• Runs of consecutive numbers with the same number and sum of divisors.at n=12A225758
• Numbers k such that the average of the divisors of k and k+1 is the same.at n=16A238380
• Numbers n such that floor(antisigma(n) / sigma(n)) = floor(antisigma(n+1) / sigma(n+1)).at n=16A244666
• Numbers k such that bsigma(k) = bsigma(k+1), where bsigma(k) is the sum of the bi-unitary divisors of k (A188999).at n=33A293183
• Numbers k such that isigma(k) = isigma(k+1), where isigma(k) is the sum of the infinitary divisors of k (A049417).at n=36A306985
• Numbers k such that t(k) = t(k+1) where t(k) = tau(k) + sigma(k) = A007503(k) is the number of subgroups of the dihedral group of order 2k.at n=6A322256
• Numbers m such that the delta(m) = abs(sigma(m+1)/(m+1) - sigma(m)/(m)) is smaller than delta(k) for all k < m.at n=24A335071
• Regular triangle T(n,k) of Dellac configurations with boundaries, n>=1 and k>=0.at n=24A343198
• Numbers k such that k and k+1 have the same number and sum of divisors but a different number of distinct prime factors.at n=0A350800