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!)
A061912 a(n) is the smallest m for which sqrt(sum of digits of m^2) = n. 8
0, 1, 2, 3, 13, 67, 264, 1667, 16667, 94863, 1643167, 29983327, 706399164, 31144643167, 1296109172867 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

a(15) <= 62441868958167. - Donovan Johnson, Jul 10 2012

LINKS

Table of n, a(n) for n=0..14.

Mathematical Reflections, Solution to Problem J307, Issue 5, 2014, p 1.

EXAMPLE

Sum of digits of 13^2 = sum of digits of 169 = 16 is the first occurrence of 4^2, so a(4) = 13.

MAPLE

f := []: a := 1: for i from 1 to 10 do for j from 1 do if sqrt(convert(convert(j^2, base, 10), `+`)) = i then f := [op(f), j]; a := j; break fi; od; od; f;

MATHEMATICA

t={}; m=0; Do[While[Sqrt[Total[IntegerDigits[m^2]]] != n, m++]; AppendTo[t, m], {n, 0, 9}]; t (* Jayanta Basu, May 06 2013 *)

PROG

(PARI) a(n) = my(k=0); while(sumdigits(k^2) != n^2, k++); k; \\ Michel Marcus, Jan 07 2017

CROSSREFS

Cf. A007953, A004159, A061909, A061910, A061911, A067072.

Cf. A067075, A286650.

Sequence in context: A068945 A219698 A293251 * A212433 A013167 A224239

Adjacent sequences:  A061909 A061910 A061911 * A061913 A061914 A061915

KEYWORD

nonn,base,more

AUTHOR

Asher Auel (asher.auel(AT)reed.edu), May 17 2001

EXTENSIONS

a(11) from John W. Layman, Jan 10 2002

a(12) from Ryan Propper, Jul 07 2005

a(13) from Zak Seidov, Jan 27 2011

a(14) from Donovan Johnson, Jul 10 2012

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 July 10 11:42 EDT 2020. Contains 335576 sequences. (Running on oeis4.)