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A080670
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Literal reading of the prime factorization of n.
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9
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1, 2, 3, 22, 5, 23, 7, 23, 32, 25, 11, 223, 13, 27, 35, 24, 17, 232, 19, 225, 37, 211, 23, 233, 52, 213, 33, 227, 29, 235, 31, 25, 311, 217, 57, 2232, 37, 219, 313, 235, 41, 237, 43, 2211, 325, 223, 47, 243, 72, 252, 317, 2213, 53, 233, 511, 237, 319, 229, 59, 2235
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Exponents equal to 1 are omitted and therefore A080670 differs from A067599.
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LINKS
| T. D. Noe, Table of n, a(n) for n = 1..10000
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EXAMPLE
| 8=2^3, which reads 23, hence a(8)=23; 12=2^2*3, which reads 223, hence a(12)=223
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MAPLE
| ifsSorted := proc(n)
local fs, L, p ;
fs := sort(convert(numtheory[factorset](n), list)) ;
L := [] ;
for p in fs do
L := [op(L), [p, padic[ordp](n, p)]] ;
end do;
L ;
end proc:
A080670 := proc(n)
local a, p ;
if n = 1 then
return 1;
end if;
a := 0 ;
for p in ifsSorted(n) do
a := digcat2(a, op(1, p)) ;
if op(2, p) > 1 then
a := digcat2(a, op(2, p)) ;
end if;
end do:
a ;
end proc: # R. J. Mathar, Oct 02 2011
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MATHEMATICA
| f[n_] := Block[{p = Flatten[ FactorInteger[n]]}, k = Length[p]; While[k > 0, If[ p[[k]] == 1, p = Delete[p, k]]; k-- ]; FromDigits[ Flatten[ IntegerDigits[p]]]]; Table[ f[n], {n, 2, 60}] (* From Robert G. Wilson v, Mar 02 2003 *)
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CROSSREFS
| Cf. A037276, A067599.
See A195330, A195331 for those n for which A080670 is a contraction.
See also home primes, A037271.
Sequence in context: A090122 A114749 A141458 * A073647 A073646 A037276
Adjacent sequences: A080667 A080668 A080669 * A080671 A080672 A080673
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KEYWORD
| nonn,base
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AUTHOR
| Jon Perry (perry(AT)globalnet.co.uk), Mar 02 2003
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EXTENSIONS
| Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 02 2003
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