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A131181 A 2-way classification of integers: complement of A026416. 3
6, 8, 10, 12, 14, 15, 18, 20, 21, 22, 26, 27, 28, 32, 33, 34, 35, 36, 38, 39, 44, 45, 46, 48, 50, 51, 52, 55, 57, 58, 60, 62, 63, 64, 65, 68, 69, 72, 74, 75, 76, 77, 80, 82, 84, 85, 86, 87, 90, 91, 92, 93, 94, 95, 96, 98, 99, 100, 106, 108, 111, 112, 115, 116, 117, 118, 119, 120, 122, 123, 124, 125, 126, 129, 132, 133, 134, 140, 141, 142, 143, 144, 145, 146, 147, 148, 150, 153, 155, 156, 158, 159, 160, 161, 162, 164, 166, 168, 171, 172, 175, 176, 177, 178, 183 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The sequence contains (for example) 140, so differs from A000379 by more than just the missing term 1. - Vladimir Shevelev, Apr 05 2013

LINKS

Table of n, a(n) for n=1..105.

MATHEMATICA

f[1]=1; f[2]=2; f[n_] := f[n] = For[k = f[n-1]+1, True, k++, If[ FreeQ[ Table[ f[i]*f[j], {i, 1, n-2}, {j, i+1, n-1}], k], Return[k]]];

A026416 = Table[f[n], {n, 1, 80}];

A131181 = Complement[ Range[ A026416 // Last], A026416] (* Jean-Fran├žois Alcover, May 16 2013 *)

CROSSREFS

Complement of A026416.

Cf. A000379.

Sequence in context: A139118 A089229 A123240 * A064176 A000379 A176525

Adjacent sequences:  A131178 A131179 A131180 * A131182 A131183 A131184

KEYWORD

nonn,easy

AUTHOR

Max Alekseyev, Sep 23 2007

STATUS

approved

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Last modified August 20 10:05 EDT 2019. Contains 326149 sequences. (Running on oeis4.)