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A256523
Numbers m such that m, m^2 and m^3 have identical initial digits in decimal representation.
3
0, 1, 10, 11, 12, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 966, 967, 968, 969, 970, 971, 972, 973, 974, 975, 976, 977, 978, 979, 980, 981, 982, 983, 984, 985
OFFSET
1,3
COMMENTS
Intersection of A089951 and A144582.
From Jianing Song, Dec 26 2022: (Start)
For k > 0, write k = s * 10^t, 1 <= s < 10, then k is a term if and only if s is in [1, 2^(1/3)) U (30^(2/3), 10).
Except for 0, terms of A144582 that start with 1 or 9. (End)
LINKS
FORMULA
A000030(a(n)) = A002993(a(n)) = A000030(A000290(a(n))) = A002994(a(n)) = A000030(A000578(a(n))).
PROG
(Haskell)
a256523 n = a256523_list !! (n-1)
a256523_list = [x | x <- [0..], let i = a000030 x,
a000030 (x ^ 2) == i, a000030 (x ^ 3) == i]
(PARI) initial(n)=digits(n)[1]
is(n)=if(n==0, return(1)); my(k=initial(n)); initial(n^2)==k && initial(n^3)==k \\ Charles R Greathouse IV, May 13 2015
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Apr 01 2015
STATUS
approved