A061957 Numbers n such that n divides the (left) concatenation of all numbers <= n written in base 4 (most significant digit on right).

1, 3, 9, 11, 63, 79, 189, 271, 507, 833, 8697, 12739, 3341049

Offset: 1

Author

Larry Reeves (larryr(AT)acm.org), May 24 2001

Keywords

• nonn
• base
• more

Comments

This sequence differs from A029521 in that all least significant zeros are kept during concatenation.

No more terms < 10^7. - Lars Blomberg, Aug 28 2011

Examples

			See A061955 for example.
		

Links

• Index entries for related sequences

Crossrefs

Cf. A029447-A029470, A029471-A029494, A029495-A029518, A029519-A029542, A061931-A061954, A061955-A061978.

Programs

Mathematica

b = 4; c = {}; Select[Range[10^4], Divisible[FromDigits[c = Join[Reverse[IntegerDigits[#, b]], c], b], #] &] (* Robert Price, Mar 07 2020 *)

PARI

lista(nn, m=4) = my(c, t); for(k=1, nn, t+=m^c*fromdigits(Vecrev(digits(k, m)), m); c+=logint(m*k, m); if(t%k==0, print1(k, ", "))); \\ Jinyuan Wang, Dec 05 2020

Extensions

Edited and updated by Larry Reeves (larryr(AT)acm.org), Apr 12 2002

a(13) from Lars Blomberg, Aug 28 2011