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A231711
Numbers n such that n > sigma(n) - sigma(n-1).
2
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
1,1
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.
LINKS
EXAMPLE
10 is in sequence because antisigma(10) = 37 > antisigma(9) = 32.
MAPLE
with(numtheory); A231711:=n->`if`(sigma(n)-sigma(n-1)<n, n, NULL); seq(A231711(n), n=1..100); # Wesley Ivan Hurt, Nov 14 2013
PROG
(PARI) isok(n) = n > sigma(n) - sigma(n-1); \\ Michel Marcus, Nov 14 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Nov 12 2013
STATUS
approved