A161643 Sum of all numbers from the smallest up to the largest prime factor of the n-th composite.

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

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