

A053247


Second differences of sigma(n) that are positive.


3



2, 7, 11, 7, 22, 24, 7, 34, 41, 14, 48, 40, 18, 68, 71, 21, 49, 75, 38, 102, 92, 100, 103, 47, 110, 96, 50, 138, 140, 15, 103, 134, 78, 195, 161, 6, 116, 194, 70, 182, 140, 72, 234, 178, 56, 156, 227, 76, 229, 218, 226, 276, 160, 260, 162, 26, 252, 280, 74, 224
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OFFSET

1,1


LINKS



FORMULA



MAPLE

with (numtheory): f := [seq( sigma(i+2)  sigma(i+1)  (sigma(i+1)  sigma(i)), i=1..200)];
seq(`if`(f[i] > 0, f[i], print( )), i=1..200);


MATHEMATICA

Select[Differences[DivisorSigma[1, Range[150]], 2], #>0&] (* Harvey P. Dale, May 10 2012 *)


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



