A075618 Rearrangement of natural numbers so that starting with a(n) the concatenation of n numbers is divisible by n. Choose the smallest number that has not already appeared if there is a choice.

1, 2, 4, 3, 5, 6, 8, 7, 10, 9, 14, 11, 12, 13, 20, 15, 22, 16, 30, 17, 28, 18, 32, 19, 31, 21, 24, 23, 35, 25, 44, 26, 48, 27, 40, 29, 49, 33, 60, 34, 53, 36, 52, 37, 50, 38, 72, 39, 75, 41, 56, 42, 64, 43, 68, 45, 67, 46, 80, 47, 83, 51, 104, 54, 71, 55, 86, 57, 95, 58, 100, 59

Offset

1,2

Links

Table of n, a(n) for n=1..72.

Example

2 divides 24, 3 divides 435, 4 divides 3568, etc.

Maple

a:=proc(n) option remember; local t, S, i; S:={$1..300} minus {seq(a(i), i=1..n-1)}; t:=min(S[]); if n::odd then while parse(cat(seq(a((n+1)/2+i), i=0..(n-3)/2), t)) mod (n+1)/2 <> 0 do S:=S minus {t}; t:=min(S[]) od fi; t end: a(1):=1: seq(a(n), n=1..186); # Alec Mihailovs

Crossrefs

Cf. A075619, A083195.

Sequence in context: A334672 A095690 A094870 * A095689 A083194 A105366

Adjacent sequences: A075615 A075616 A075617 * A075619 A075620 A075621

Keyword

base,nonn

Author

Amarnath Murthy, Sep 29 2002

Extensions

More terms from Alec Mihailovs (alec(AT)mihailovs.com), Jul 05 2004

Status

approved