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Search: id:A121369
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A121369 a(1) = a(2) = 1, a(n) = A007947(a(n-1))+A007947(a(n-2)) for n >= 3, i.e. a(n)=the largest squarefree divisor of a(n-1) plus the largest squarefree divisor of a(n-2). +0
3
1, 1, 2, 3, 5, 8, 7, 9, 10, 13, 23, 36, 29, 35, 64, 37, 39, 76, 77, 115, 192, 121, 17, 28, 31, 45, 46, 61, 107, 168, 149, 191, 340, 361, 189, 40, 31, 41, 72, 47, 53, 100, 63, 31, 52, 57, 83, 140, 153, 121, 62, 73, 135, 88, 37, 59, 96, 65, 71, 136, 105, 139, 244, 261, 209, 296 (list; graph; listen)
OFFSET

1,3

LINKS

Leroy Quet, Home Page (listed in lieu of email address)

EXAMPLE

6 is the largest squarefree divisor of a(12) = 36. 29 is the largest squarefree divisor of a(13) = 29. So a(14) = 6 + 29 = 35.

MAPLE

with(numtheory): A007947:= proc(n) local i, t1, t2; t1 := ifactors(n)[2]; t2 := mul(t1[i][1], i=1..nops(t1)); end: a:=proc(n) if n=1 or n=2 then 1 else A007947(a(n-1))+A007947(a(n-2)) fi end: seq(a(n), n=1..20); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Jul 24 2006

CROSSREFS

Cf. A007947, A121367, A121368.

Sequence in context: A010074 A116918 A116917 this_sequence A125727 A112337 A141804

Adjacent sequences: A121366 A121367 A121368 this_sequence A121370 A121371 A121372

KEYWORD

nonn

AUTHOR

Leroy Quet Jul 23 2006

EXTENSIONS

More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Jul 24 2006

More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 18 2007

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Last modified November 29 12:46 EST 2009. Contains 167659 sequences.


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