A218980 Integers not in A218852.

1, 2, 3, 4, 6, 8, 9, 11, 12, 17, 18, 22, 23, 24, 29, 30, 36, 37, 41, 47, 48, 53, 59, 60, 67, 71, 72, 79, 83, 89, 97, 101, 107, 113, 120, 127, 131, 137, 144, 149, 157, 163, 167, 173, 179, 180, 191, 197, 210, 211, 223, 227, 233, 239, 240, 251, 257, 263, 269, 277

Offset

1,2

Comments

Conjecture: This sequence is infinite.

Links

Table of n, a(n) for n=1..60.

Prog

(JavaScript)
function divisorSum(n) {
c=0;
for (i=1; i<=n; i++) if (n%i==0) c+=i;
return c;
}
ds=new Array();
for (j=1; j<1001; j++) ds[j]=divisorSum(j);
a=new Array();
ac=0;
for (j=1; j<300; j++)
for (k=1; k<=j; k++)
for (m=1; m<=k; m++)
if (ds[j]+ds[k]+ds[m]==ds[j+k+m]) a[ac++]=j+k+m;
a.sort(function(a, b) {return a-b; });
i=0;
while(i++<a.length-1)
if (a[i]==a[i+1]) a.splice(i--, 1);
document.writeln(a);
b=new Array();
ac=0;
bc=0;
for (i=0; i<a[a.length-1]; i++) if (a[ac]!=i) b[bc++]=i; else ac++;
document.writeln(b);

Crossrefs

Cf. A218852.

Sequence in context: A002479 A010458 A354620 * A084829 A018649 A341159

Adjacent sequences: A218977 A218978 A218979 * A218981 A218982 A218983

Keyword

nonn

Author

Jon Perry, Nov 08 2012

Status

approved