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A230123 Lowest number of the form 11*m+1 with exactly n prime factors, counted with multiplicity. 1
1, 23, 34, 12, 56, 243, 144, 320, 2432, 1728, 1024, 17920, 20736, 12288, 57344, 248832, 147456, 327680, 2490368, 1769472, 1048576, 18350080, 21233664, 12582912, 58720256, 254803968, 150994944, 335544320, 2550136832, 1811939328, 1073741824, 18790481920 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..31.

FORMULA

a(n) = a(n-10)*2^10 for n >= 13.

EXAMPLE

The lowest number of the form 11m+1 with exactly 8 prime factors is 2^7*19 = 11*221+1 = 2432

MATHEMATICA

Join[{1}, Table[k = 1; While[Total[Transpose[FactorInteger[11*k + 1]][[2]]] != n, k++]; 11*k + 1, {n, 20}]] (* T. D. Noe, Oct 10 2013 *)

CROSSREFS

Sequence in context: A043909 A145566 A146595 * A049851 A223606 A120147

Adjacent sequences:  A230120 A230121 A230122 * A230124 A230125 A230126

KEYWORD

nonn

AUTHOR

Elliott Line, Oct 10 2013

EXTENSIONS

Typo in Mathematica code fixed by Vincenzo Librandi, Oct 11 2013

STATUS

approved

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Last modified May 19 17:48 EDT 2019. Contains 323395 sequences. (Running on oeis4.)