A074399 - OEIS

This site is supported by donations to The OEIS Foundation.

A074399

Largest prime divisor of n(n+1).

2, 3, 3, 5, 5, 7, 7, 3, 5, 11, 11, 13, 13, 7, 5, 17, 17, 19, 19, 7, 11, 23, 23, 5, 13, 13, 7, 29, 29, 31, 31, 11, 17, 17, 7, 37, 37, 19, 13, 41, 41, 43, 43, 11, 23, 47, 47, 7, 7, 17, 17, 53, 53, 11, 11, 19, 29, 59, 59, 61, 61, 31, 7, 13, 13, 67, 67, 23, 23, 71, 71, 73, 73, 37, 19 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`Størmer shows that a(n) tends to infinity with n.`
	LINKS	`Carl Størmer, Quelques théorèmes sur l'équation de Pell x^2 - Dy^2 = ±1 et leurs applications, Skrifter udgivne af Videnskabsselskabet i Christiania: Mathematisk-naturvidenskabelig Klasse (1897).`
	FORMULA	`Max (A006530(2n), A006530(2n+2)).`
	MATHEMATICA	`Table[ Last[ Table[ # [[1]]] & /@ FactorInteger[n^2 - 1]], {n, 3, 160, 2}]`
	CROSSREFS	`Bisection of A076605.` `Cf. A037464. Essentially the same as A069902.` `Sequence in context: A167411 A112823 A185075 * A090302 A093074 A136548` `Adjacent sequences: A074396 A074397 A074398 * A074400 A074401 A074402`
	KEYWORD	`nonn,easy`
	AUTHOR	`N. J. A. Sloane (njas(AT)research.att.com), Nov 29 2002`
	EXTENSIONS	`Extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Dec 02 2002`

Content is available under The OEIS End-User License Agreement .

Last modified February 15 20:26 EST 2012. Contains 205852 sequences.