OFFSET
1,3
COMMENTS
Second differences give A053223, for n>1.
If the first term is changed to 1, this is also the first differences of A001065. - N. J. A. Sloane, Jan 17 2023
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = A053222(n) - 1, for n>1
MAPLE
with(numtheory): seq( sigma(i+1) - sigma(i) - 1, i=2..100); # for n>1
MATHEMATICA
Chowlan[n_] := If[n == 1, 0, DivisorSigma[1, n] - n - 1]; Table[Chowlan[n + 1] - Chowlan[n], {n, 1, 100}] (* G. C. Greubel, Sep 03 2018 *)
Differences[Join[{0}, Table[DivisorSigma[1, n]-n-1, {n, 2, 100}]]] (* Harvey P. Dale, Dec 19 2022 *)
PROG
(Magma) [0] cat [DivisorSigma(1, n+1) - DivisorSigma(1, n) - 1: n in [2..100]]; // G. C. Greubel, Sep 03 2018
(PARI) concat([0], vector(100, n, n++; sigma(n+1) - sigma(n) -1)) \\ G. C. Greubel, Sep 03 2018
CROSSREFS
KEYWORD
sign
AUTHOR
Asher Auel, Jan 10 2000
STATUS
approved