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Search: id:A078613
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A078613 Same numbers of distinct prime factors of forms 4*k+1 and 4*k+3. +0
1
1, 2, 4, 8, 15, 16, 30, 32, 35, 39, 45, 51, 55, 60, 64, 70, 75, 78, 87, 90, 91, 95, 102, 110, 111, 115, 117, 119, 120, 123, 128, 135, 140, 143, 150, 153, 155, 156, 159, 174, 175, 180, 182, 183, 187, 190, 203, 204, 215, 219, 220, 222, 225, 230, 234, 235, 238, 240 (list; graph; listen)
OFFSET

1,2

COMMENT

A005089(a(n)) = A005091(a(n)); A001221(a(n)) is even; if m is in the sequence, then also 2*m.

Conjecture : a(n) is asymptotic to c*n where c is around 4 - Benoit Cloitre (benoit7848c(AT)orange.fr), Jan 06 2003

EXAMPLE

n = 99 = [(4*0+3)^2]*[(4*1+1)], therefore 99 is a term.

CROSSREFS

Cf. A072202.

Sequence in context: A019278 A084345 A084561 this_sequence A072202 A076351 A140117

Adjacent sequences: A078610 A078611 A078612 this_sequence A078614 A078615 A078616

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Dec 10 2002

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Last modified December 15 00:47 EST 2009. Contains 170825 sequences.


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