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

 

Logo

The OEIS is looking to hire part-time people to help edit core sequences, upload scanned documents, process citations, fix broken links, etc. - Neil Sloane, njasloane@gmail.com

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A240924 Digital root of squares of numbers not divisible by 2, 3 or 5. 2
1, 4, 4, 7, 1, 1, 7, 4, 7, 1, 7, 4, 4, 7, 1, 7, 4, 7, 1, 1, 7, 4, 4, 1, 1, 4, 4, 7, 1, 1, 7, 4, 7, 1, 7, 4, 4, 7, 1, 7, 4, 7, 1, 1, 7, 4, 4, 1, 1, 4, 4, 7, 1, 1, 7, 4, 7, 1, 7, 4, 4, 7, 1, 7, 4, 7, 1, 1, 7, 4, 4, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

This period 24 repeating sequence is palindromic.

LINKS

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

EXAMPLE

The first 8 numbers not divisible by 2, 3 or 5 are 1,7,11,13,17,19,23,29; with squares 1,49,121,169,289,361,529,841 and digital root sequence of 1,4,4,7,1,1,7,4.

PROG

(Python)

A240924 = [1 + (n*n-1) % 9 for n in range(1, 10**3, 2) if n % 3 and n % 5 ]

# Chai Wah Wu, Sep 03 2014

CROSSREFS

Cf. A007775, A166923.

Sequence in context: A257606 A090531 A198138 * A282468 A196463 A021695

Adjacent sequences:  A240921 A240922 A240923 * A240925 A240926 A240927

KEYWORD

nonn,base,easy

AUTHOR

Gary Croft, Aug 15 2014

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 May 28 12:19 EDT 2017. Contains 287241 sequences.