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A053227
First differences of sigma(n) that are negative.
4
1, 4, 2, 6, 14, 13, 19, 10, 12, 29, 2, 26, 40, 15, 6, 53, 4, 48, 52, 6, 6, 24, 67, 21, 44, 48, 40, 30, 106, 43, 76, 30, 72, 121, 44, 88, 65, 42, 116, 12, 90, 122, 40, 24, 154, 15, 115, 112, 18, 30, 54, 170, 64, 134, 96, 28, 2, 36, 227, 18, 68, 184, 79, 120, 176, 132, 148
OFFSET
1,2
LINKS
FORMULA
a(n) = A053222(A053226(n))
MAPLE
with(numtheory): seq( `if`((sigma(i) > sigma(i+1)), (sigma(i) - sigma(i+1)), print( )), i=1..200);
MATHEMATICA
Abs[Select[Differences[DivisorSigma[1, Range[200]]], #<0&]] (* Harvey P. Dale, Apr 17 2022 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Asher Auel, Jan 06 2000
STATUS
approved