A230123 - OEIS

A230123

Smallest number of the form 11*m+1 with exactly n prime factors, counted with multiplicity.

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

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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 smallest number of the form 11*m+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