The On-Line Encyclopedia of Integer Sequences (OEIS)

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A053225

First differences of sigma(n) that are positive.
(history; published version)

#6 by N. J. A. Sloane at Fri Oct 27 22:00:45 EDT 2023

AUTHOR

_Asher Auel (asher.auel(AT)reed.edu), _, Jan 06 2000

Discussion

Fri Oct 27

22:00

OEIS Server: https://oeis.org/edit/global/2974

#5 by Peter Luschny at Fri Nov 22 03:43:43 EST 2019

STATUS

proposed

approved

#4 by Michel Marcus at Fri Nov 22 03:43:25 EST 2019

STATUS

editing

proposed

#3 by Michel Marcus at Fri Nov 22 03:43:22 EST 2019

AUTHOR

Asher Auel (asher.auel(AT)reed.edu) , Jan 06 2000

STATUS

approved

editing

#2 by N. J. A. Sloane at Fri May 16 03:00:00 EDT 2003

MAPLE

with (numtheory): seq( `if`((sigma(i) < sigma(i+1)), (sigma(i+1)-sigma(i)), print( )) , , i=1..139);

CROSSREFS

Cf. A000203, A053222, A053227.

KEYWORD

nonn,new

nonn

AUTHOR

Asher Auel (asher.auel@(AT)reed.edu) Jan 6, 06 2000

#1 by N. J. A. Sloane at Mon May 08 03:00:00 EDT 2000

NAME

First differences of sigma(n) that are positive.

DATA

2, 1, 3, 6, 7, 5, 16, 10, 7, 21, 22, 4, 36, 11, 16, 42, 31, 6, 43, 22, 34, 54, 40, 76, 36, 26, 66, 48, 10, 108, 34, 8, 23, 60, 58, 48, 123, 40, 10, 16, 72, 106, 5, 140, 24, 60, 144, 56, 16, 132, 73, 61, 114, 106, 172, 106, 96, 126, 66, 216, 53, 56, 156, 127, 76, 204, 44, 36

OFFSET

1,1

FORMULA

a(n) = A053222(A053224(n))

MAPLE

with (numtheory): seq( `if`((sigma(i) < sigma(i+1)), (sigma(i+1)-sigma(i)), print( )) , i=1..139);

CROSSREFS

Cf. A000203, A053222, A053227

KEYWORD

nonn

AUTHOR

Asher Auel (asher.auel@reed.edu) Jan 6, 2000

STATUS

approved