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

1,2

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

Links

Table of n, a(n) for n=1..13.

Index entries for related sequences

Example

See A061955 for example.

Mathematica

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

Prog

(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

Crossrefs

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

Sequence in context: A135365 A088877 A069871 * A136984 A168400 A310318

Adjacent sequences: A061954 A061955 A061956 * A061958 A061959 A061960

Keyword

nonn,base,more

Author

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

Extensions

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

a(13) from Lars Blomberg, Aug 28 2011

Status

approved