A050622 -id:A050622 - cp's OEIS frontend

A053378 a(n) contains n digits (either '5' or '8') and is divisible by 2^n.

8, 88, 888, 5888, 85888, 885888, 8885888, 58885888, 558885888, 8558885888, 58558885888, 858558885888, 5858558885888, 85858558885888, 585858558885888, 5585858558885888, 55585858558885888, 855585858558885888

Offset: 1

Henry Bottomley, Mar 06 2000

Ray Chandler, Table of n, a(n) for n = 1..1000

Cf. A023413, A050621, A050622, A035014.

a(n)=a(n-1)+10^(n-1)*(8-3*[a(n-1)/2^(n-1) mod 2]) i.e. a(n) ends with a(n-1); if (n-1)-th term is divisible by 2^n then n-th term begins with an 8, if not then n-th term begins with a 5.

A053379 a(n) contains n digits (either '7' or '8') and is divisible by 2^n.

Original entry on oeis.org

8, 88, 888, 7888, 77888, 877888, 7877888, 87877888, 787877888, 8787877888, 88787877888, 888787877888, 8888787877888, 88888787877888, 788888787877888, 8788888787877888, 88788888787877888, 888788888787877888

Offset: 1

Henry Bottomley, Mar 06 2000

Ray Chandler, Table of n, a(n) for n = 1..1000

Cf. A023414, A050621, A050622, A035014.

a(n)=a(n-1)+10^(n-1)*(8-[a(n-1)/2^(n-1) mod 2]) i.e. a(n) ends with a(n-1); if (n-1)-th term is divisible by 2^n then n-th term begins with an 8, if not then n-th term begins with a 7.

A241882 Numbers with d digits that are divisible by 2^d and have at most 2 distinct digits: exactly one even digit and at most one odd digit.

Original entry on oeis.org

2, 4, 6, 8, 12, 16, 32, 36, 44, 52, 56, 72, 76, 88, 92, 96, 112, 144, 232, 272, 336, 344, 544, 552, 616, 656, 696, 744, 776, 888, 944, 992, 1616, 1888, 2112, 2272, 2992, 3232, 3344, 3888, 4144, 4544, 4944, 5552, 5888, 6336, 6656, 7744, 7776, 7888, 9696, 9888

Offset: 1

J. Lowell, Apr 30 2014

Union of 20 different sequences, all of which are defined as "a(n) contains n digits (either [any odd digit] or [any nonzero even digit] and is divisible by 2^n)."

Subsequence of A050622. - Michel Marcus, May 07 2014

			24 is not in the sequence because it has distinct even digits.

Ray Chandler, Table of n, a(n) for n = 1..10000

Cf. A035014, A053312-A053318, A053332-A053338, A053376-A053380 (sequences whose union is this sequence).

isok(n) = {digs = digits(n); d = #digs; if (n % 2^d, return (0)); sd = Set(digs); if (#sd > 2, return (0)); if (#sd < 2, return (1)); ((sd[1] % 2) + (sd[2] % 2)) == 1;} \\ Michel Marcus, May 02 2014

More terms from Michel Marcus, May 02 2014

cp's OEIS Frontend

A053378 a(n) contains n digits (either '5' or '8') and is divisible by 2^n.

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A053379 a(n) contains n digits (either '7' or '8') and is divisible by 2^n.

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A241882 Numbers with d digits that are divisible by 2^d and have at most 2 distinct digits: exactly one even digit and at most one odd digit.

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