A231711 Numbers n such that n > sigma(n) - sigma(n-1).

3, 4, 5, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 19, 21, 22, 23, 25, 26, 27, 28, 29, 31, 32, 33, 34, 35, 37, 38, 39, 40, 41, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 55, 56, 57, 58, 59, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 81, 82

Offset: 1

Author

Jaroslav Krizek, Nov 12 2013

Keywords

• nonn

Comments

Numbers n such that antisigma(n) > antisigma(n-1), where antisigma(n) = A024816(n) = the sum of the non-divisors of n that are between 1 and n.

Numbers n such that A163553(n-1) > 0.

Numbers n such that antisigma(n) < antisigma(n-1) = A231547.

Numbers n such that antisigma(n) = antisigma(n-1) = A231545.

Complement of union of A231547, A231545 and number 1.

Examples

			10 is in sequence because antisigma(10) = 37 > antisigma(9) = 32.
		

Links

• Jaroslav Krizek, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A231545, A231546, A231547, A231548, A024816, A163553.

Programs

Maple

with(numtheory); A231711:=n->`if`(sigma(n)-sigma(n-1)A231711(n), n=1..100); # Wesley Ivan Hurt, Nov 14 2013

PARI

isok(n) = n > sigma(n) - sigma(n-1); \\ Michel Marcus, Nov 14 2013