A250305 a(0) = 1; a(n+1) is the smallest number not in the sequence such that a(n+1) - Sum_{i=1..n} a(i) divides a(n+1) + Sum_{i=1..n} a(i).

1, 2, 4, 5, 6, 9, 18, 15, 20, 40, 60, 90, 135, 243, 216, 288, 384, 512, 1024, 1536, 2304, 3456, 5184, 7776, 11664, 17496, 26244, 39366, 59049, 118098, 98415, 131220, 174960, 233280, 311040, 414720, 552960, 737280, 983040, 1310720, 2621440, 3932160, 5898240, 8847360

Offset

0,2

Comments

If a(0) = 2, the sequence is the same; only a(0) and a(1) switch places.

Links

Table of n, a(n) for n=0..43.

Prog

(PARI) v=[1]; print1(1, ", "); n=1; while(n<10^4, if((V=vecsum(v))!=n&&(V+n)\(V-n)==(V+n)/(V-n)&&!vecsearch(vecsort(v), n), v=concat(v, n); print1(n, ", "); n=0); n++)

Crossrefs

Cf. A250306.

Sequence in context: A288429 A163116 A003306 * A136585 A122721 A014224

Adjacent sequences: A250302 A250303 A250304 * A250306 A250307 A250308

Keyword

nonn

Author

Derek Orr, Jan 15 2015

Status

approved