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A196520
Smallest Friedman number of order n.
0
25, 279936, 31381059609, 1125899906842624, 1152921504606846976, 4722366482869645213696, 42391158275216203514294433201, 324518553658426726783156020576256
OFFSET
1,1
COMMENTS
More terms from a=9 to a=12 are 22528399544939174411840147874772641, 147808829414345923316083210206383297601, 1427247692705959881058285969449495136382746624 and 91343852333181432387730302044767688728495783936.
FORMULA
All numbers of this kind are perfect powers.
EXAMPLE
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.
CROSSREFS
Sequence in context: A122500 A347812 A251362 * A228536 A191559 A279039
KEYWORD
nonn,base
AUTHOR
Kausthub Gudipati, Oct 03 2011
STATUS
approved