id:A139542 - OEIS Search Results

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a(n) = a(n-1) + largest divisor of a(n-1) <= sqrt(a(n-1)).

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1, 2, 3, 4, 6, 8, 10, 12, 15, 18, 21, 24, 28, 32, 36, 42, 48, 54, 60, 66, 72, 80, 88, 96, 104, 112, 120, 130, 140, 150, 160, 170, 180, 192, 204, 216, 228, 240, 255, 270, 285, 300, 315, 330, 345, 360, 378, 396, 414, 432, 450, 468, 486, 504, 525, 546, 567, 588, 609 (list; graph; listen)

	OFFSET	`1,2`
	EXAMPLE	`Term after 36 is 42 because largest divisor of 36 <= sqrt(36) is 6 and 36+6=42`
	MATHEMATICA	`a = {1}; Do[AppendTo[a, a[[ -1]] + Max[Select[Divisors[a[[ -1]]], # <= Sqrt[a[[ -1]]] &]]], {60}]; a [From Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Aug 28 2008]`
	CROSSREFS	`Sequence in context: A130519 A001972 A005705 this_sequence A093717 A002093 A067069` `Adjacent sequences: A139539 A139540 A139541 this_sequence A139543 A139544 A139545`
	KEYWORD	`nonn`
	AUTHOR	`J. Lowell (jhbubby(AT)mindspring.com), Jun 10 2008`
	EXTENSIONS	`More terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Aug 28 2008`

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Last modified December 18 21:37 EST 2009. Contains 171024 sequences.

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