how to look up a sequence (and avoid duplicates)

[N. J. A. Sloane]

see if it is in the OEIS, 
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sequences; and for that I am thankful. But still there are many sequences 
sequences, maybe duplicates will be reduced in that way as well.
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Subject: Sequences of weights
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Dear seqfans,

Below the graphs ln(weight);ln(level) for :
natural numbers ln(A020639);ln(A032742) (sieve of Eratosthenes, numbers of level
1 = primes) :
http://reismann.free.fr/naturalDecomp.html

primes numbers ln(A117078);ln(A117563) :
http://reismann.free.fr/primesDecomp.html

odd numbers weight= A090368 :
http://reismann.free.fr/oddDecomp.html

even numbers weight= A117871 :
http://reismann.free.fr/evenDecomp.html

and an interesting graph ln(A006530);ln(A052126) :
http://reismann.free.fr/naturalLargestDecomp.html

On the OEIS :
Weight of natural numbers or least prime dividing n : A020639
http://www.research.att.com/~njas/sequences/table?a=20639&fmt=5
Weight of prime numbers : A117078
http://www.research.att.com/~njas/sequences/table?a=117078&fmt=5
and Largest prime dividing n (with a(1)=1) : A006530
http://www.research.att.com/~njas/sequences/table?a=6530&fmt=5

Good thoughts,

Rémi



Straightforward duplicates:

A126613 and A127936
A098767 and A098901
A083434 and A086548
A052382 and A102349
A081211 and A081213
A079715 and A104589


Possible duplicates:

A067139 and A078645
http://www.research.att.com/~njas/sequences/?q=id:A067139|id:A078645

A088669 and A091580
http://www.research.att.com/~njas/sequences/?q=id:A088669|id:A091580

A072061 and A095721 (possibility noted in comments to A095721)
http://www.research.att.com/~njas/sequences/?q=id:A072061|id:A095721

A034287 and A067128 (possibility noted in comments to A067128)
http://www.research.att.com/~njas/sequences/?q=id:A034287|id:A067128