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A227982
Numbers n such that sigma(n+1) - sigma(n-1) > sigma(n); where sigma(n) = A000203(n) = sum of the divisors of n.
2
47, 59, 83, 107, 119, 143, 167, 179, 215, 239, 251, 263, 299, 335, 359, 383, 395, 419, 431, 467, 479, 503, 527, 539, 587, 599, 623, 629, 647, 659, 671, 719, 755, 767, 779, 839, 863, 887, 899, 923, 935, 959, 983, 1007, 1019, 1055, 1079, 1091, 1103, 1139, 1175
OFFSET
1,1
COMMENTS
See A076530 - numbers n such that sigma(n+1) - sigma(n-1) = sigma(n).
Complement of union of A076530, A227983 and number 1.
LINKS
EXAMPLE
Number 59 is in the sequence because sigma(60) - sigma(58) = 168 - 90 = 78 > sigma(59) = 60.
MATHEMATICA
Flatten[Position[Partition[DivisorSigma[1, Range[1200]], 3, 1], _?(Last[#]- First[#]> #[[2]]&), {1}, Heads->False]]+1 (* Harvey P. Dale, Mar 31 2014 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Aug 08 2013
STATUS
approved