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A068890 a(1) = 1; a(n) = smallest nontrivial n-th power with property that digits alternate in parity. 1
1, 4, 8, 16, 32, 729, 2187, 256 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Conjecture: the sequence is finite.

For all n>=1, (n^10 mod 1000) is one of {0, 1, 24, 49, 176, 201, 224, 249, 376, 401, 424, 449, 576, 601, 624, 625, 649, 776, 801, 824, 849, 976}. None of these have digits of alternating parity, thus a(10) does not exist. - Benjamin Chaffin, Nov 24 2021

LINKS

Table of n, a(n) for n=1..8.

CROSSREFS

Cf. A030152, A068891.

Sequence in context: A049932 A272712 A020161 * A073856 A019458 A264166

Adjacent sequences:  A068887 A068888 A068889 * A068891 A068892 A068893

KEYWORD

nonn,base,fini

AUTHOR

Amarnath Murthy, Mar 20 2002

STATUS

approved

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Last modified October 3 09:13 EDT 2022. Contains 357231 sequences. (Running on oeis4.)