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A072202
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Same numbers of prime factors of forms 4*k+1 and 4*k+3, counted with multiplicity.
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4
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1, 2, 4, 8, 15, 16, 30, 32, 35, 39, 51, 55, 60, 64, 70, 78, 87, 91, 95, 102, 110, 111, 115, 119, 120, 123, 128, 140, 143, 155, 156, 159, 174, 182, 183, 187, 190, 203, 204, 215, 219, 220, 222, 225, 230, 235, 238, 240, 246, 247, 256, 259, 267, 280, 286, 287, 291
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Equivalently, numbers n such that A083025(n) = A065339(n).
Closed under multiplication.
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LINKS
| Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
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EXAMPLE
| 825 = 3*5*5*11 = [(4*0+3)*(4*2+3)]*[(4*1+1)*(4*1+1)], therefore 825 is a term.
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MATHEMATICA
| f[n_]:=Plus@@Last/@Select[If[==1, {}, FactorInteger[n]], Mod[#[[1]], 4]==1&]; Table[f[n], {n, 100}] (* Ray Chandler, Dec 18 2011 *)
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PROG
| (Haskell)
a072202 n = a072202_list !! (n-1)
a072202_list = [x | x <- [1..], a083025 x == a065339 x]
-- Reinhard Zumkeller, Jan 10 2012
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CROSSREFS
| Cf. A002144, A002145, A202237 (odd elements), A079635.
Primitive elements are {2} U A080774. - Franklin T. Adams-Watters, Dec 16 2011.
Sequence in context: A084345 A084561 A078613 * A076351 A140117 A039743
Adjacent sequences: A072199 A072200 A072201 * A072203 A072204 A072205
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KEYWORD
| nonn
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AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jul 03 2002
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