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!)
A257766 Numbers n such that the sum of the digits of n times the square of the sum of the digits squared of n equals n. 2
1, 2023, 2400, 52215, 615627, 938600, 1648656 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Sequence is finite since it cannot contain numbers of 9 or more digits. Indeed a number of 9 digits is at least equal to 10^8, but the function computed here for a number of n digits is at most (9*n)*(9^2*n)^2, which for n=9 is 43046721 < 10^8. - Giovanni Resta, May 08 2015

LINKS

Table of n, a(n) for n=1..7.

EXAMPLE

52215 is in the sequence because 52215 = (5+2+2+1+5)*(5^2+2^2+2^2+1^2+5^2)^2.

MATHEMATICA

Select[Range@1648656, #==Total[IntegerDigits[#]] *Total[IntegerDigits[#]^2]^2&] (* Ivan N. Ianakiev, May 08 2015 *)

CROSSREFS

Cf. A115518.

Sequence in context: A119423 A176913 A013687 * A126821 A333057 A156855

Adjacent sequences:  A257763 A257764 A257765 * A257767 A257768 A257769

KEYWORD

base,nonn,fini,full

AUTHOR

Pieter Post, May 07 2015

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 May 18 09:26 EDT 2021. Contains 343995 sequences. (Running on oeis4.)