A227981 Numbers n such that sigma(n-1) - sigma(n+1) < sigma(n); where sigma(n) = A000203(n) = sum of the divisors of n.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 62, 63, 64, 65, 66, 67, 68, 69, 70

Offset

1,2

Comments

There is no number n < 100000 such that sigma(n-1) - sigma(n+1) = sigma(n).

Complement of A227980.

Links

Jaroslav Krizek, Table of n, a(n) for n = 1..2000

Example

Number 60 is in the sequence because sigma(59) - sigma(61) = 60 - 62 = -2 < sigma(60) = 168.

Crossrefs

Cf. A000203, A227980.

Sequence in context: A144972 A166719 A272159 * A085736 A265711 A262065

Adjacent sequences: A227978 A227979 A227980 * A227982 A227983 A227984

Keyword

nonn

Author

Jaroslav Krizek, Aug 02 2013

Status

approved