login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A237608 Number of n-digit numbers that are divisible by a square and have the same property if any number of rightmost digits is deleted. 0
3, 14, 61, 263, 1128, 4788, 20271, 85885, 364408, 1546394, 6563924, 27863816, 118286561 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

See A237607 for the numbers themselves and for more comments.

The ratio r(n) = a(n+1)/a(n) seems to converge to a constant value of about 4.245...

LINKS

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

Stanislav Sykora, PARI/GP scripts for genetic threads

EXAMPLE

One-digit numbers k with moebius(k)=0 are 4, 8 and 9. Hence a(1) = 3.

PROG

(PARI) See the link (use GT_DivMod0 with "IsMoebiusZero" for the "property" argument).

CROSSREFS

Cf. A237607.

Sequence in context: A006502 A024037 A281349 * A100295 A091701 A242637

Adjacent sequences:  A237605 A237606 A237607 * A237609 A237610 A237611

KEYWORD

nonn,hard,more,base

AUTHOR

Stanislav Sykora, Feb 15 2014

EXTENSIONS

a(12)-a(13) from Lars Blomberg, Jan 02 2016

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified June 28 16:56 EDT 2017. Contains 288839 sequences.