A227982 Numbers n such that sigma(n+1) - sigma(n-1) > sigma(n); where sigma(n) = A000203(n) = sum of the divisors of n.

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

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

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

Cf. A076530, A000203, A227983.

Sequence in context: A061758 A309510 A046503 * A102274 A139909 A368077

Adjacent sequences: A227979 A227980 A227981 * A227983 A227984 A227985

Keyword

nonn

Author

Jaroslav Krizek, Aug 08 2013

Status

approved