OFFSET
1,1
COMMENTS
"In 1700, Charles de Neuveglise claimed the product of two consecutive integers n(n+1) with n>=3 is abundant." - Tattersall, p. 133.
REFERENCES
James J. Tattersall, Elementary Number Theory in Nine Chapters, Cambridge University Press, 2001.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1001 from Harvey P. Dale)
Charles de Neuveglise, Traité methodique et abregé de toutes les mathématiques, tome 2 (L’arithmétique ou Science des nombres), Trevoux, 1700, pp. 244-246.
Leonard Eugene Dickson, History of the Theory of Numbers, Washington, Carnegie Institution of Washington, 1919, p. 15.
FORMULA
MATHEMATICA
Select[Table[n(n+1), {n, 300}], DivisorSigma[1, #]<2#&] (* Harvey P. Dale, Oct 03 2011 *)
PROG
(PARI) for(n=1, 350, o=n*(n+1); if(sigma(o)<2*o, print1(o, ", ")))
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Jason Earls, Dec 03 2002
EXTENSIONS
Offset corrected by Amiram Eldar, Mar 11 2024
STATUS
approved