A083539 a(n) = sigma(n) * sigma(n+1): product of sigma-values for consecutive integers.

3, 12, 28, 42, 72, 96, 120, 195, 234, 216, 336, 392, 336, 576, 744, 558, 702, 780, 840, 1344, 1152, 864, 1440, 1860, 1302, 1680, 2240, 1680, 2160, 2304, 2016, 3024, 2592, 2592, 4368, 3458, 2280, 3360, 5040, 3780, 4032, 4224, 3696, 6552, 5616, 3456, 5952

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Mathematica

f[x_] := DivisorSigma[1, x] t=Table[f[w+1]*f[w], {w, 1, 128}]
Times@@@Partition[DivisorSigma[1, Range[50]], 2, 1] (* Harvey P. Dale, May 21 2014 *)

Prog

(PARI) a(n)=sigma(n)*sigma(n+1) \\ Charles R Greathouse IV, Feb 14 2013

Crossrefs

Cf. A000203, A060781, A060780, A083538, A330322.

Sequence in context: A083543 A083538 A060781 * A237426 A066643 A140065

Adjacent sequences: A083536 A083537 A083538 * A083540 A083541 A083542

Keyword

nonn

Author

Labos Elemer, May 21 2003

Status

approved