login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A323287 Number of different numbers that can be obtained from (the decimal expansion of) n by one step of the Choix de Bruxelles, version 1 (A323286) operation. 4
1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 3, 5, 3, 5, 3, 5, 3, 5, 3, 2, 4, 6, 4, 6, 4, 6, 4, 6, 4, 2, 3, 5, 3, 5, 3, 5, 3, 5, 3, 2, 4, 6, 4, 6, 4, 6, 4, 6, 4, 2, 3, 5, 3, 5, 3, 5, 3, 5, 3, 2, 4, 6, 4, 6, 4, 6, 4, 6, 4, 2, 3, 5, 3, 5, 3, 5, 3, 5, 3, 2, 4, 6, 4, 6, 4, 6, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

This is the number of terms in row n of the irregular triangle in A323286.

This is one less than the number of different numbers that can be obtained from (the decimal expansion of) n by one step of the Choix de Bruxelles, version 2 (A323460) operation. In other words this is one less than the number of terms in row n of the irregular triangle in A323460.

LINKS

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Eric Angelini, Lars Blomberg, Charlie Neder, Remy Sigrist, and N. J. A. Sloane, "Choix de Bruxelles": A New Operation on Positive Integers, arXiv:1902.01444, Feb 2019; Fib. Quart. 57:3 (2019), 195-200.

EXAMPLE

From 12 we can reach any of 6,11,14,22,24, so a(12) = 5.

PROG

(PARI) a(n, base=10) = { my (d=digits(n, base), s=Set()); for (w=1, #d, for (l=0, #d-w, if (d[l+1], my (h=d[1..l], m=fromdigits(d[l+1..l+w], base), t=d[l+w+1..#d]); s = setunion(s, Set(fromdigits(concat([h, digits(m*2, base), t]), base))); if (m%2==0, s = setunion(s, Set(fromdigits(concat([h, digits(m/2, base), t]), base))))))); #s } \\ Rémy Sigrist, Jan 15 2019

CROSSREFS

Cf. A323286, A323460.

Sequence in context: A161300 A161275 A160979 * A167679 A051881 A338731

Adjacent sequences:  A323284 A323285 A323286 * A323288 A323289 A323290

KEYWORD

nonn,base

AUTHOR

N. J. A. Sloane, Jan 14 2019

EXTENSIONS

More terms from Rémy Sigrist, Jan 15 2019

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 23 03:56 EDT 2021. Contains 347609 sequences. (Running on oeis4.)