A054002 - OEIS

%I #17 Oct 27 2023 22:00:45

%S 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,

%T 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,

%U 16,12,8,48,32,8,24,24,16,16,16,8,16,24,64,8,16,16,16,16,64,24,32,60

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

%H Amiram Eldar, <a href="/A054002/b054002.txt">Table of n, a(n) for n = 1..10135</a> (from the b-file at A002961)

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

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

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

%K nonn

%O 1,1

%A _Asher Auel_, Jan 12 2000

%E More terms from _Naohiro Nomoto_, Jun 23 2001