A196520 Smallest Friedman number of order n.

25, 279936, 31381059609, 1125899906842624, 1152921504606846976, 4722366482869645213696, 42391158275216203514294433201, 324518553658426726783156020576256

Offset: 1

Author

Kausthub Gudipati, Oct 03 2011

Keywords

• nonn
• base

Comments

More terms from a=9 to a=12 are 22528399544939174411840147874772641, 147808829414345923316083210206383297601, 1427247692705959881058285969449495136382746624 and 91343852333181432387730302044767688728495783936.

Examples

			Since 25 is the smallest Friedman number, it is the smallest Friedman number of order 1.
279936 = 6^7 = (9 - 3)^(9 - 2), together using the digits of the number itself. Hence it is the smallest Friedman number of order 2.
31381059609 = 9^11 = 9^(5+6) = 3^(30-8+0), together using the digits of the number itself. Hence it is the smallest Friedman number of order 3.
		

Links

• Erich Friedman, Problem of the Month May 2010

Crossrefs

Cf. A036057

Formula

All numbers of this kind are perfect powers.