This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A083539 a(n) = sigma(n) * sigma(n+1): product of sigma-values for consecutive integers. 8
 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 (list; graph; refs; listen; history; text; internal format)
 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. 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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 16 02:52 EDT 2019. Contains 328038 sequences. (Running on oeis4.)