A224792 Smallest skinny number (A061909) with digit sum n.

0, 1, 2, 3, 13, 113, 1113, 11113, 1011113, 101011113, 1101111211, 110101111211, 100110101111211, 10101010101101122, 1011111111100000013, 1010111111111000000022, 111000010111000111111111, 1010110111101110100000011111, 1111111110010101100001100000102

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 * A062447 A153888 A068083

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