A067500 -id:A067500 - cp's OEIS frontend

A118872 Numbers k such that digit sum of 3^k is a power of 3.

0, 1, 2, 3, 4, 5, 9, 10, 11, 13, 16, 17, 21, 27, 31, 35, 36, 39, 114, 119, 973, 1005, 1010, 1025, 3006, 3029, 3040, 9128, 9215, 9227, 9316, 27431, 27442, 27515, 27519, 27554, 82632, 82746, 82763, 82784, 83111, 246838, 247206, 247388, 247406, 247447, 741310, 742154

Offset: 1

Zak Seidov, May 24 2006

a(47) > 677750. - Ray Chandler, Jun 16 2006

a(47) <= 741310. If a(47) < 741310 then a(47) < 720000. a(48) <= 742154. If a(48) < 741310 then a(48) < 720000. - David A. Corneth, Nov 23 2022

			3^39 = 4052555153018976267 with digit sum 81 = 3^4, so 39 is a term.

Cf. A004166 (sum of digits of 3^n).

Do[If[IntegerQ[Log[3, Plus @@ IntegerDigits[3^n]]], Print[n]], {n, 0, 677750}];

is(n) = my(s = sumdigits(3^n)); s == 3^logint(s, 3) \\ David A. Corneth, Nov 23 2022

A067500(n) = 3^a(n).

Extended by Ray Chandler, Jun 16 2006

a(47) and a(48) from Jon E. Schoenfield, Nov 25 2022

A067510 Powers of 6 with digit sum divisible by 6.

Original entry on oeis.org

6, 1296, 279936, 1679616, 10077696, 60466176, 13060694016, 78364164096, 2821109907456, 16926659444736, 101559956668416, 3656158440062976, 789730223053602816, 4738381338321616896, 28430288029929701376

Offset: 1

Amarnath Murthy, Feb 11 2002

Robert Israel, Table of n, a(n) for n = 1..630

Cf. A067499, A067500, A067501, A067502, A067503, A067504, A067505, A067506, A067507, A067508, A067509.

Intersection of A000400 and A054683.

select(n -> convert(convert(n,base,10),`+`)::even, [seq(6^i, i=1..100)]); # Robert Israel, Apr 20 2020

Offset changed by Robert Israel, Apr 20 2020

A067511 Powers of 7 with digit sum divisible by 7.

Original entry on oeis.org

7, 2401, 117649, 40353607, 1977326743, 9387480337647754305649, 65712362363534280139543, 459986536544739960976801, 15286700631942576193765185769276826401, 5243338316756303634461458718861951455543, 12589255298531885026341962383987545444758743

Offset: 1

Amarnath Murthy, Feb 11 2002

Andrew Howroyd, Table of n, a(n) for n = 1..150

Intersection of A000420 and A273159.

Cf. A067499, A067500, A067501, A067502, A067503, A067504, A067505, A067506, A067507, A067508, A067509, A067510.

lista(n)={my(L=List(),k=0);while(#LAndrew Howroyd, Sep 17 2024

More terms from Sascha Kurz, Mar 18 2002

Offset changed and a(10) onwards from Andrew Howroyd, Sep 17 2024

cp's OEIS Frontend

A118872 Numbers k such that digit sum of 3^k is a power of 3.

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A067510 Powers of 6 with digit sum divisible by 6.

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Maple

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A067511 Powers of 7 with digit sum divisible by 7.

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Extensions