A289273 Complement of A242410.

4, 25, 26, 27, 28, 30, 32, 35, 36, 39, 40, 55, 56, 65, 66, 69, 70, 72, 74, 75, 76, 78, 80, 95, 96, 105, 106, 108, 110, 114, 116, 121, 122, 123, 124, 126, 128, 132, 134, 135, 136, 140, 141, 143, 144, 145, 146, 147, 148, 153, 154, 155, 156, 161, 162, 165, 166

Offset

1,1

Comments

Conjecture: there will never be a point where this sequence has more terms than A242410. (80 is only the 21st term of this sequence.)

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

A242410:= proc(n) option remember; local Q, k;
     Q:= map(procname, numtheory:-divisors(n) minus {1, n});
     for k from procname(n-1) + 1 do
       if andmap(t -> (k mod t > 0), Q) then return k fi
     od
end proc:
A242410(1):= 1:
sort(convert({$1..A242410(1000)} minus map(A242410, {$1..1000}), list)); # Robert Israel, Jul 05 2017

Mathematica

a = {1}; Do[k = a[[n - 1]] + 1; While[AnyTrue[Most@ Rest@ Divisors@ n, Divisible[k, a[[#]] ] &], k++]; AppendTo[a, k], {n, 2, 110}]; Complement[Range@ Max@ a, a] (* Michael De Vlieger, Jul 05 2017 *)

Prog

(PARI) okd(k, vd) = {for (i=1, #vd, if ((k % vd[i]) == 0, return (0)); ); return (1); }
fnext(n, va) = {d = divisors(n); vd = vector(#d-2, i, va[d[i+1]]); k = va[n-1]+1; while (! okd(k, vd), k++); k; }
lista(nn) = {va = vector(nn); va[1] = 1; for (n=2, nn, va[n] = fnext(n, va); ); va; }

Crossrefs

Cf. A242410.

Sequence in context: A302624 A238515 A043067 * A309056 A095970 A297963

Adjacent sequences: A289270 A289271 A289272 * A289274 A289275 A289276

Keyword

nonn

Author

J. Lowell, Jun 30 2017

Status

approved