This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
A069530 := proc(n) local m ; if modp(n,3) = 0 then 0 ; else for m from 1 do if digsum(m*n) = 11 then return m*n ; end if; end do: end if; end proc: seq(A069530(n),n=1..70) ; # R. J. Mathar, Aug 06 2019
sod(n) = {digs = digits(n); return (sum(i=1, #digs, digs[i]));}
a(n) = {if (n % 3 == 0, return (0)); k = 1; while (sod(k*n) != 11, k++); k;} \\ Michel Marcus, Sep 14 2013
unfinished:= true: V:= Vector(300): V0:= select(t -> igcd(t, 3*11*37*101*271) = 1, {$1..300}):
for i1 from 0 while unfinished do
for i2 from 0 to i1 while unfinished do
for i3 from 0 to i2 while unfinished do
for i4 from 0 to i3 while unfinished do
for i5 from 0 to i4 while unfinished do
for i6 from 0 to i5 while unfinished do
for i7 from 0 to i6 while unfinished do
v:= 10^i1 + 10^i2 + 10^i3 + 10^i4 + 10^i5 + 10^i6 + 10^i7;
dv:= numtheory:-divisors(v);
for s in V0 intersect dv do
V[s]:= v;
od;
V0:= V0 minus dv;
unfinished:= evalb(V0 <> {});
od od od od od od od:
convert(V,list); # Robert Israel, Feb 13 2024
unfinished:= true: V:= Vector(1000):
V0:= select(t -> igcd(t, 3*4649) = 1 and t mod 1111 <> 0 and t mod 2849 <> 0 and t mod 3367 <> 0 and t mod 5291 <> 0, {$1..1000}):
for i1 from 0 while unfinished do
for i2 from 0 to i1 while unfinished do
for i3 from 0 to i2 while unfinished do
for i4 from 0 to i3 while unfinished do
for i5 from 0 to i4 while unfinished do
for i6 from 0 to i5 while unfinished do
for i7 from 0 to i6 while unfinished do
for i8 from 0 to i7 while unfinished do
for i9 from 0 to i8 while unfinished do
for i10 from 0 to i9 while unfinished do
v:= 10^i1 + 10^i2 + 10^i3 + 10^i4 + 10^i5 + 10^i6 + 10^i7 + 10^i8 + 10^i9 + 10^i10;
if convert(convert(v,base,10),`+`) <> 10 then next fi;
dv:= numtheory:-divisors(v);
for s in V0 intersect dv do
V[s]:= v;
od;
V0:= V0 minus dv;
unfinished:= evalb(V0 <> {});
od od od od od od od od od od:
convert(V,list); # Robert Israel, Feb 14 2024
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