A250747 Start with a(0) = 0; then a(n) = smallest number not already in the sequence such that a(n) divides concat(a(n), a(n-1), ..., a(0)).

0, 1, 2, 3, 5, 10, 6, 9, 13, 26, 15, 18, 30, 431, 73, 67, 134, 7, 14, 21, 35, 29, 58, 127, 27, 39, 43, 70, 11, 22, 19, 38, 95, 190, 2748070932534311, 2768821759897, 5537643519794, 787, 191, 382, 955, 17, 31, 45, 54, 90, 101, 202, 303, 57, 114, 47, 55, 33, 66

Offset

0,3

Comments

Like A250746, but without the constraint a(n) > a(n-1).

Links

Jon E. Schoenfield, Table of n, a(n) for n = 0..165

Example

a(0) = 0;
a(1) = 1 -> 10 / 1 = 10;
a(2) = 2 -> 210 / 2 = 105;
a(3) = 3 -> 3210 / 3 = 1070;
Now we cannot use 4 as the next term because 43210 / 4 = 21605 / 2.
a(4) = 5 -> 32105 / 5 = 6421;
Again, we cannot use 4, 6, 7, 8 or 9.
a(5) = 10 -> 1053210 / 10 = 105321.
We still cannot use 4, but 6 is ok.
a(6) = 6 -> 61053210 / 6 = 10175535. Etc.

Maple

with(numtheory); P:=proc(q) local a, b, k, n; print(0); print(1); a:=10; b:={0, 1};
for k from 1 to q do for n from 1 to q do if nops({n} intersect b)<1
then if type((n*10^(1+ilog10(a))+a)/n, integer)
then a:=n*10^(1+ilog10(a))+a; b:= b union {n}; print(n); break; fi; fi;
od; od; end: P(10^5);

Crossrefs

Cf. A171785, A240588, A241811, A249398, A249399, A250745, A250746.

Sequence in context: A129500 A250745 A109204 * A241262 A244489 A367297

Adjacent sequences: A250744 A250745 A250746 * A250748 A250749 A250750

Keyword

nonn,base

Author

Paolo P. Lava, Nov 28 2014

Extensions

More terms from Jon E. Schoenfield, Nov 29 2014

Status

approved