A030152 -id:A030152 - cp's OEIS frontend

A068890 a(1) = 1; a(n) = smallest nontrivial n-th power with property that digits alternate in parity.

1, 4, 8, 16, 32, 729, 2187, 256

Offset: 1

Amarnath Murthy, Mar 20 2002

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

Cf. A030152, A068891.

A068888 Squares with property that digits alternate in parity individually as well as in concatenation with previous terms.

Original entry on oeis.org

1, 4, 9, 25, 49, 81, 256, 361, 676, 729, 4761, 6561, 41616, 56169, 69696, 72361, 87616, 96721, 212521, 214369, 290521, 436921, 452929, 458329, 474721, 670761, 690561, 2143296, 3470769, 4145296, 5230369, 8503056, 9078169, 21058921, 21836929, 21874329, 25230529

Offset: 0

Amarnath Murthy, Mar 20 2002

Cf. A030152.

Missing 81 and 452929 inserted, incorrect 93636 removed, and more terms from Sean A. Irvine, Mar 22 2024

A229040 Fibonacci numbers in which parity of the decimal digits alternates.

Original entry on oeis.org

0, 1, 2, 3, 5, 8, 21, 34, 89, 610, 987, 4181, 6765

Offset: 1

Jonathan Vos Post, Sep 12 2013

No more values through F(19000). - R. J. Mathar, Jun 30 2020

Cf. A000045, A030141, A030152, A030144.

isA030141 := proc(n)
    dgs := convert(n,base,10) ;
    for i from 2 to nops(dgs) do
        if modp(op(i,dgs),2) = modp(op(i-1,dgs),2) then
            return false;
        end if;
    end do:
    true ;
end proc:
for i from 0 do
    f := combinat[fibonacci](i) ;
    if isA030141(f) then
        print(f) ;
    end if;
end do: # R. J. Mathar, Mar 13 2015

A000045 INTERSECTION A030141.

cp's OEIS Frontend

A068890 a(1) = 1; a(n) = smallest nontrivial n-th power with property that digits alternate in parity.

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A068888 Squares with property that digits alternate in parity individually as well as in concatenation with previous terms.

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Extensions

A229040 Fibonacci numbers in which parity of the decimal digits alternates.

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