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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A062685 Smallest square with digit sum n (or 0 if no such square exists). 2
1, 0, 0, 4, 0, 0, 16, 0, 9, 64, 0, 0, 49, 0, 0, 169, 0, 576, 289, 0, 0, 1849, 0, 0, 4489, 0, 3969, 17956, 0, 0, 6889, 0, 0, 27889, 0, 69696, 98596, 0, 0, 97969, 0, 0, 499849, 0, 1887876, 698896, 0, 0, 2778889, 0, 0, 4999696, 0, 9696996, 19998784, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

a(n) > 0 iff n mod 9 is 0, 1, 4, or 7. - Jon E. Schoenfield, Jul 06 2018

LINKS

Jon E. Schoenfield, Table of n, a(n) for n = 1..228 (first 213 terms from Giovanni Resta)

EXAMPLE

16 is the smallest square with digit sum 7, so a(7)=16.

MATHEMATICA

Array[If[FreeQ[{1, 4, 7, 9}, FixedPoint[Total@ IntegerDigits@ # &, #]], 0, Block[{k = 1, s}, While[Total@ IntegerDigits@ Set[s, k^2] != #, k++]; s]] &, 57] (* Michael De Vlieger, Jul 06 2018 *)

CROSSREFS

Cf. A004159, A056991.

Sequence in context: A262227 A069026 A133851 * A192016 A028699 A019259

Adjacent sequences:  A062682 A062683 A062684 * A062686 A062687 A062688

KEYWORD

base,nonn

AUTHOR

Erich Friedman, Jul 04 2001

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 October 19 09:28 EDT 2018. Contains 316339 sequences. (Running on oeis4.)