A320272 Indices (starting at 0) of integers in the increasing sequence S of nonnegative numbers that are representable in base 3/2 with digits {0, 1, 2}.

0, 1, 3, 6, 11, 17, 25, 34, 46, 60, 77, 96, 117, 142, 169, 200, 232, 268, 308, 353, 401, 453, 508, 568, 631, 699, 771, 847, 929, 1015, 1108, 1205, 1308, 1415, 1527, 1644, 1767, 1896, 2029, 2169, 2315, 2468, 2626, 2790, 2961, 3140, 3325, 3519, 3719, 3924, 4138, 4357, 4585, 4817, 5057, 5305, 5561, 5823, 6094, 6372, 6658

Offset

1,3

Comments

Base 3/2 representations are considered with nonnegative exponents only (i.e., ending at the radix point).

Odd-indexed terms of this sequence form A320035. The sequence S is essentially the same as in A320035 under multiplication of digits by 2 (i.e., under substitution H->1, 1->2).

a(n) is the number of positive numbers less than n that are representable in base 3/2 with digits {0, 1, 2}. - Max Alekseyev, Oct 12 2018

Links

Table of n, a(n) for n=1..61.

Formula

For all k >= 1, a(2*k-1) = A320035(k).

Example

The sequence S starts with "0", "1"=1, "10"=3/2, "2", "100"=9/4, "11"=5/2, "20"=3, "101"=13/4, "1000"=27/8, ....
The indices of first four integers in S are a(1)=0, a(2)=1, a(3)=3, and a(4)=6.

Crossrefs

Cf. A320035.

Sequence in context: A263807 A176708 A273140 * A119639 A281376 A247586

Adjacent sequences: A320269 A320270 A320271 * A320273 A320274 A320275

Keyword

base,nonn

Author

Tanya Khovanova and PRIMES STEP Junior group, Oct 08 2018

Extensions

Edited by Max Alekseyev, Oct 12 2018

Status

approved