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A053230
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First differences between n for which sigma(n) < sigma(n+1).
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9
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1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 4, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 4, 2, 2, 2, 2, 4, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 2
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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COMMENTS
| It seems that the expansion consists of only {1,2,3,4}.
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FORMULA
| a(n) = A053224(n+1) - A053224(n).
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MAPLE
| with(numtheory): f := [seq( `if`((sigma(i+1) > sigma(i)), i, print( )), i=1..5000)];
seq( f[i+1] - f[i], i=1..2000);
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MATHEMATICA
| Differences[Select[Range[250], DivisorSigma[1, #]<DivisorSigma[ 1, #+1]&]] (* From Harvey P. Dale, Apr 30 2011 *)
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CROSSREFS
| Cf. A000203, A053224, A053231, A053232, A053233, A053234, A053235, A053236, A053237, A053238.
Sequence in context: A110592 A185714 A168353 * A194334 A048766 A105516
Adjacent sequences: A053227 A053228 A053229 * A053231 A053232 A053233
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KEYWORD
| nonn,nice
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AUTHOR
| Asher Auel (asher.auel(AT)reed.edu) Jan 10, 2000
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