A131181 - OEIS

A131181

A 2-way classification of integers: complement of A026416.

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-François Alcover, May 16 2013 *)

CROSSREFS