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A036336
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Smallest positive integer with n digits and exactly n prime factors (counted with multiplicity).
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7
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2, 10, 102, 1012, 10010, 100040, 1000125, 10000096, 100000032, 1000000080, 10000000080, 100000000512, 1000000001280, 10000000014336, 100000000004096, 1000000000010880, 10000000000008192, 100000000000008192, 1000000000000010240, 10000000000000045056
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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LINKS
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David A. Corneth, Table of n, a(n) for n = 1..29
Carlos Rivera, Puzzle 25. Composed primes, The Prime Puzzles and Problems Connection.
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MAPLE
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f:= proc(n) local k;
for k from 10^(n-1) do
if numtheory:-bigomega(k) = n then return k fi
od
end proc:
map(f, [$1..20]); # Robert Israel, May 31 2018
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MATHEMATICA
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npf[n_]:=Module[{k=1, st=10^(n-1)-1}, While[PrimeOmega[st+k]!=n, k++]; st+k]; Array[npf, 20] (* Harvey P. Dale, Mar 25 2012 *)
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PROG
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(Python)
from sympy import factorint
def a(n):
for m in range(10**(n-1), 10**n):
if sum(factorint(m).values()) == n: return m
print([a(n) for n in range(1, 13)]) # Michael S. Branicky, Feb 10 2021
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CROSSREFS
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Cf. A036335, A036337, A036338.
Sequence in context: A228120 A074109 A291101 * A070842 A086927 A342108
Adjacent sequences: A036333 A036334 A036335 * A036337 A036338 A036339
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KEYWORD
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nonn,base
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AUTHOR
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Patrick De Geest, Dec 15 1998
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EXTENSIONS
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More terms from Matthew Conroy, May 27 2001
Offset corrected, and a(19)-a(20) from Robert Israel, May 31 2018
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STATUS
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approved
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