A025561 - OEIS

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A025561

a(n) = sum of the exponents in the prime factorization of LCM{1, n-1, ..., C(n-[ n/2 ],[ n/2 ])}.

0

0, 0, 1, 1, 3, 3, 4, 4, 6, 6, 7, 7, 8, 8, 9, 8, 10, 10, 11, 11, 12, 11, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 18, 17, 18, 17, 18, 18, 19, 18, 19, 19, 20, 20, 21, 20, 21, 21, 22, 22, 23, 22, 23, 23, 24, 23, 24, 23, 24, 24, 25, 25, 26, 25, 27, 26, 27, 27, 28, 27, 28, 28, 29, 29, 30

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OFFSET

1,5

LINKS

Table of n, a(n) for n=1..75.

FORMULA

a(n) = A001222(A025560(n)). - Sean A. Irvine, Sep 06 2019

CROSSREFS

Cf. A001222, A025560.

Sequence in context: A083522 A355067 A108942 * A342169 A187321 A145814

Adjacent sequences: A025558 A025559 A025560 * A025562 A025563 A025564

KEYWORD

nonn

AUTHOR

Clark Kimberling

EXTENSIONS

More terms from Sean A. Irvine, Sep 06 2019

STATUS

approved