A112321 Least n-digit number whose square is exclusionary, or 0 if no such number exists.

2, 17, 157, 1547, 15094, 203879, 0, 0, 0

Offset: 1

Author

Lekraj Beedassy and Klaus Brockhaus, Sep 08 2005

Keywords

• nonn
• base
• fini

Comments

m has an exclusionary square if m consists of distinct digits and m^2 is made up only of digits not appearing in m.

a(10) = 0 since 10-digit numbers either use all digits or at least one digit more than once; a(n) = 0 for n > 10 since numbers with more than 10 digits use at least one digit more than once.

References

• H. Ibstedt, Solution to Problem 2623 "Exclusionary Powers", Journal of Recreational Mathematics pp. 346-9 Vol. 32 no. 4 2003-4 Baywood NY.

Crossrefs

Cf. A112322 (corresponding squares), A110815.