login
A128993
A table which contains in each row two or more perfect powers with the same digits.
0
125, 512, 144, 441, 169, 196, 961, 243, 324, 256, 625, 1024, 2401, 1089, 9801, 1296, 2916, 9216, 1369, 1936, 1728, 2187, 1764, 4761, 2197, 7921, 4096, 9604, 10201, 12100, 10404, 14400, 40401, 44100, 10609, 16900, 19600, 61009, 90601, 96100
OFFSET
1,1
COMMENTS
Perfect powers, A001597, may have anagrams (obtained by permutation of the digits, excluding anagrams with leading zeros) which are again perfect powers. Each row of the table collects a set of at least two different anagrams which are perfect powers.
Requiring at least two different representations in a row means that numbers like 81 = 3^4 = 9^2, which are in A117453, do not necessarily populate a row on their own.
The table is sorted such that entries in the first column are increasing, and such that each perfect power appears at most once.
EXAMPLE
The table starts with the first 11 rows as follows:
125,512; 125=5^3 and 512 = 2^9 = 8^3
144,441; 144=12^2 and 441=21^2
169,196,961; 169=13^2 and 196=14^2 and 961=31^2
243,324; 243=3^5 and 324=18^2
256,625; 256 = 16^2=4^4 and 625=25^2=5^4
1024,2401; 1024=2^10=32^2 and 2401=49^2=7^4
1089,9801; 1089=33^2 and 9801=99^2
1296,2916,9216; 1296=36^2 and 2916=54^2 and 9216=96^2
1369,1936; 1369=37^2 and 1936=44^2
1728,2187; 1728=12^3 and 2187=3^7
1764,4761; 1764=42^2 and 4761=69^2
CROSSREFS
Cf. A117453.
Sequence in context: A250136 A141480 A155986 * A061450 A067974 A034290
KEYWORD
nonn,base,tabf
AUTHOR
J. M. Bergot, Apr 30 2007
EXTENSIONS
Edited, and most terms replaced by R. J. Mathar, Nov 02 2009
STATUS
approved