id:A112337 - OEIS Search Results

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a(1)=1, a(2) = 2. a(n) = a(n-2) + (largest prime dividing a(n-1)).

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1, 2, 3, 5, 8, 7, 15, 12, 18, 15, 23, 38, 42, 45, 47, 92, 70, 99, 81, 102, 98, 109, 207, 132, 218, 241, 459, 258, 502, 509, 1011, 846, 1058, 869, 1137, 1248, 1150, 1271, 1191, 1668, 1330, 1687, 1571, 3258, 1752, 3331, 5083, 3354, 5126, 3587, 5337, 4180, 5356 (list; graph; listen)

	OFFSET	`1,2`
	EXAMPLE	`a(13) = a(11) + (largest prime dividing a(12)). a(12) is 38, and 19 is the largest prime dividing it. So a(13) = 23 + 19 = 42.`
	PROGRAM	`(MuPAD): A := array(1..100); A[1] := 1; A[2] := 2; for n from 3 to 100 do s := ifactor(A[n-1]); b := s[nops(s)-1]; A[n] := A[n-2] + b; print(A[n]); end_for; (Steinerberger)`
	CROSSREFS	`Cf. A078695, A006530.` `Sequence in context: A116917 A121369 A125727 this_sequence A141804 A121368 A010073` `Adjacent sequences: A112334 A112335 A112336 this_sequence A112338 A112339 A112340`
	KEYWORD	`nonn`
	AUTHOR	`Leroy Quet (qq-quet(AT)mindspring.com), Dec 01 2005`
	EXTENSIONS	`More terms from Stefan Steinerberger (hansibal(AT)hotmail.com), Dec 02 2005`

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Last modified July 26 23:19 EDT 2008. Contains 142293 sequences.

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