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A224792 Smallest skinny number (A061909) with digit sum n. 1
0, 1, 2, 3, 13, 113, 1113, 11113, 1011113, 101011113, 1101111211, 110101111211, 100110101111211, 10101010101101122, 1011111111100000013, 1010111111111000000022, 111000010111000111111111, 1010110111101110100000011111, 1111111110010101100001100000102 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

The smallest m >= 0 with sum of digits of (m) = n and sum of digits of (m^2) = (sum of digits of (m))^2.

There are infinitely many natural numbers m >= 0 with sum of digits of (m) = n and sum of digits of (m^2) = (sum of digits of (m))^2.

LINKS

Hiroaki Yamanouchi, Table of n, a(n) for n = 0..19

FORMULA

a(n) > 2/9 * 10^(n/2) for n > 4. - Charles R Greathouse IV, Apr 18 2013

MATHEMATICA

DS[n_] := Total[IntegerDigits[n]]; nn = 10; t = Table[0, {nn}]; n = 0; found = 0; While[n++; r = FromDigits[IntegerDigits[n, 4]]; found < nn, If[DS[r]^2 == DS[r^2] && DS[r] <= nn && t[[DS[r]]] == 0, t[[DS[r]]] = r;  found++; Print[r]]]; Join[{0}, t] (* T. D. Noe, Apr 18 2013 *)

CROSSREFS

Cf. A061909.

Sequence in context: A125283 A098406 A280012 * A153888 A068083 A137459

Adjacent sequences:  A224789 A224790 A224791 * A224793 A224794 A224795

KEYWORD

nonn,base

AUTHOR

Reiner Moewald, Apr 18 2013

EXTENSIONS

a(10) corrected and a(11) added by T. D. Noe, Apr 18 2013

a(12)-a(13) from Donovan Johnson, Apr 19 2013

a(14) from Donovan Johnson, Apr 24 2013

a(15)-a(18) from Hiroaki Yamanouchi, Aug 28 2014

STATUS

approved

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Last modified August 3 05:51 EDT 2020. Contains 336197 sequences. (Running on oeis4.)