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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
OFFSET
1,1
FORMULA
a(n) = A000217(A052369(n))-A000217(A056608(n)-1). - R. J. Mathar, Jun 16 2009
EXAMPLE
For n = 5, the 5th composite is 10 = 2*5. a(5) = 2+3+4+5 = 14.
CROSSREFS
Cf. A002808.
Sequence in context: A129396 A274602 A153289 * A196982 A197167 A197782
KEYWORD
nonn,less
AUTHOR
EXTENSIONS
Replaced 80 by 90 in two places, R. J. Mathar, Jun 16 2009
STATUS
approved