A226797 - OEIS

A226797

Number of n-digit numbers x such that the digits of x^2 occur with frequency 1.

10, 49, 162, 220, 170, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

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OFFSET

1,1

COMMENTS

After a(5), all terms are 0.

LINKS

Table of n, a(n) for n=1..85.

EXAMPLE

All numbers 0 to 9 have squares containing only digits of frequency 1: 0, 1, 4, 9, 16, 25, 36, 49, 64, 81.

MATHEMATICA

cnt = 0; x = 0; t2 = Table[While[x < 10^n, If[Union[Last[Transpose[Tally[IntegerDigits[x^2]]]]] == {1}, cnt++]; x++]; cnt, {n, 5}]; Differences[Join[{0}, t2]]

CROSSREFS

Cf. A225428, A226796.

Sequence in context: A056578 A370216 A307904 * A163716 A271662 A244864

Adjacent sequences: A226794 A226795 A226796 * A226798 A226799 A226800

KEYWORD

nonn,base

AUTHOR

T. D. Noe, Jun 21 2013

STATUS

approved