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A080613 Minimal sequence such that Omega(a(m))<=Omega(a(n)) for m<n, where Omega=A001222 (sum of exponents in prime factorization). 1
1, 2, 3, 4, 25, 6, 49, 8, 27, 20, 1331, 12, 2197, 28, 45, 16, 83521, 36, 130321, 40, 189, 88, 279841, 24, 625, 104, 81, 56, 707281, 60, 923521, 32, 891, 272, 4375, 72, 69343957, 304, 1053, 80, 115856201, 168, 147008443, 176, 405, 368, 229345007, 48 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n)=n iff n=2^k or n=3*2^k (A029744); A001222(a(n))=A000523(n).

LINKS

Table of n, a(n) for n=1..48.

FORMULA

a(1) = 1, a(n) = if Omega(n)<Omega(a(n-1)) then n*spf(n)^(Omega(a(n-1))-Omega(n)) else n, where spf=A020639 (smallest prime factor).

CROSSREFS

Sequence in context: A000336 A287433 A235041 * A055006 A139050 A043309

Adjacent sequences:  A080610 A080611 A080612 * A080614 A080615 A080616

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Feb 25 2003

STATUS

approved

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Last modified April 4 20:01 EDT 2020. Contains 333229 sequences. (Running on oeis4.)