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 A161643 Sum of all numbers from the smallest up to the largest prime factor of the n-th composite. 0
 2, 5, 2, 3, 14, 5, 27, 12, 2, 5, 14, 25, 65, 5, 5, 90, 3, 27, 14, 2, 63, 152, 18, 5, 189, 88, 14, 27, 65, 12, 275, 5, 7, 14, 150, 90, 5, 56, 27, 187, 434, 14, 495, 25, 2, 81, 65, 152, 273, 27, 5, 702, 12, 189, 45, 90, 14, 3, 860, 27, 143, 945, 432, 65, 14, 70, 275, 493, 1127, 180, 5, 27 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..72. FORMULA a(n) = A000217(A052369(n))-A000217(A056608(n)-1). [R. J. Mathar, Jun 16 2009] EXAMPLE a(1)=2=2). a(2)=5=2+3. a(3)=2=2. a(4)=3=3. a(5)=14=2+3+4+5. a(6)=5=2+3. a(7)=27=2+3+4+5+6+7. CROSSREFS Cf. A002808. Sequence in context: A129396 A274602 A153289 * A196982 A197167 A197782 Adjacent sequences: A161640 A161641 A161642 * A161644 A161645 A161646 KEYWORD nonn,less AUTHOR Juri-Stepan Gerasimov, Jun 15 2009 EXTENSIONS Replaced 80 by 90 in two places, R. J. Mathar, Jun 16 2009 STATUS approved

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Last modified September 18 01:35 EDT 2024. Contains 375995 sequences. (Running on oeis4.)