cp's OEIS Frontend

A091783 Numbers with digits in nondecreasing order such that sum of the reciprocals of the digits is 1.

%I A091783 #19 Dec 12 2015 03:14:11
%S A091783 1,22,236,244,333,2488,2666,3366,3446,4444,26999,28888,33999,34688,
%T A091783 36666,44488,44666,55555,366999,368888,446999,448888,466688,666666,
%U A091783 3999999,4688999,4888888,6666999,6668888,7777777,66999999,68888999,88888888,999999999
%N A091783 Numbers with digits in nondecreasing order such that sum of the reciprocals of the digits is 1.
%C A091783 236 is a member but 263, 326, 362, 623, 632 which are digit permutations of 236 are not included (unlike A037268).
%C A091783 By definition, this is a subsequence of A052382 (zeroless numbers). - _Michel Marcus_, Jul 06 2015
%e A091783 236 is a member as 1/2 + 1/3 + 1/6 = 1.
%p A091783 F:= proc(t,ns) option remember;
%p A091783    local n0, k,r;
%p A091783    if ns = [] then
%p A091783       if t = 0 then return {[]}
%p A091783       else return {}
%p A091783       fi;
%p A091783    fi;
%p A091783    n0:= ns[1];
%p A091783    `union`(seq(map(r -> [k,op(r)], procname(t - k/n0, ns[2..-1])),k=0..floor(t*n0)));
%p A091783 end proc:
%p A091783 g:= proc(t) local L,i; L:= [seq(i$t[i],i=1..9)]; add(L[i]*10^(nops(L)-i),i=1..nops(L)) end proc:
%p A091783 sort(convert(map(g,F(1,[$1..9])),list)); # _Robert Israel_, Jul 06 2015
%o A091783 (PARI) lista(nn) = {for (n=1, nn, d = digits(n); if (vecmin(d) && (vecsort(d)==d) && (sum(k=1, #d, 1/d[k])==1), print1(n, ", ")););} \\ _Michel Marcus_, Jul 06 2015
%Y A091783 Cf. A037268, A052382.
%K A091783 base,fini,nonn,full
%O A091783 1,2
%A A091783 _Amarnath Murthy_, Feb 17 2004
%E A091783 More terms from Sam Handler (sam_5_5_5_0(AT)yahoo.com), Apr 17 2004
%E A091783 Incorrect term 39999 corrected to 33999 by _Thomas Oléron Evans_, Jul 06 2015