A137116 Numbers k such that k and k^2 use only the digits 2, 5, 7, 8 and 9.

5, 27, 77, 85, 527, 727, 7227, 9777, 28277, 29585, 88277, 99277, 278527, 298827, 2788527, 2789227, 5289227, 8875727, 9889277, 22925527, 27797977, 29879585, 52898827, 85298827, 88875527, 99789227, 99988777, 278889277, 287279585, 292898827, 297875527, 299929585, 527252527, 528982977, 727528527, 727825527, 727925527, 988579585, 992587527

Offset: 1

Author

Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008

Keywords

• base
• nonn

Comments

Generated with DrScheme.

Examples

			727872928279585^2 = 529798999722297889227927772225.
		

Links

• Michael S. Branicky, Table of n, a(n) for n = 1..578 (through 20 digits; first 180 terms from Jonathan Wellons)
• Jonathan Wellons, Tables of Shared Digits [archived].

Crossrefs

Cf. A137110, A137117.

Programs

Python

# uses auptod in A137110
print(auptod(16, only="25789")) # Michael S. Branicky, May 27 2021