A054002 Number of divisors of n such that n and n-1 have the same sum of divisors.

4, 6, 4, 8, 16, 8, 8, 12, 12, 8, 4, 10, 8, 4, 8, 12, 8, 16, 16, 16, 16, 8, 16, 12, 16, 16, 8, 8, 4, 16, 8, 24, 16, 4, 16, 8, 4, 32, 8, 16, 16, 16, 8, 8, 8, 8, 16, 32, 8, 8, 16, 16, 16, 12, 16, 16, 12, 8, 48, 32, 8, 24, 24, 16, 16, 16, 8, 16, 24, 64, 8, 16, 16, 16, 16, 64, 24, 32, 60

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10135 (from the b-file at A002961)

Formula

a(n) = tau(A002961(n) + 1).

Prog

(Magma) [#Divisors(n):n in [2..3500000]| SumOfDivisors(n) eq SumOfDivisors(n-1)]; // Marius A. Burtea, Sep 07 2019

Crossrefs

Cf. A000005, A000203, A002961, A053249, A054003.

Sequence in context: A055166 A202243 A130762 * A010300 A113209 A367731

Adjacent sequences: A053999 A054000 A054001 * A054003 A054004 A054005

Keyword

nonn

Author

Asher Auel, Jan 12 2000

Extensions

More terms from Naohiro Nomoto, Jun 23 2001

Status

approved