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A215511 A sequence of prime numbers expressed as minimum bases using only digits 0 and 1. 1
10, 10, 11, 101, 111, 1011, 10001, 10011, 11101, 11111, 11101, 10011, 10111, 101111 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,1

COMMENTS

3 = 10 base 3 = 3 + 0

5 = 10 base 5 = 5 + 0

7 = 11 base 6 = 6 + 1

37 = 101 base 6 = 36 + 0 + 1

43 = 111 base 6 = 36 + 6 + 1

223 = 1011 base 6 = 216 + 0 + 6 + 1

1297 = 10001 base 6 = 1296 + 0 + 0 + 0 + 1

1303 = 10011 base 6 = 1296 + 0 + 0 + 6 + 1

1549 = 11101 base 6 = 1296 + 216 + 36 + 0 + 1

2801 = 11111 base 7 = 2401 + 343 + 49 + 7 + 1

4673 = 11101 base 8 = 4096 + 512 + 64 + 0 + 1

6571 = 10011 base 9 = 6561 + 0 + 0 + 9 + 1

10111 = 10111 base 10 = 10000 + 0 + 100 + 10 + 1

101111 = 101111 base 10 = 100000 + 0 + 1000 + 100 + 10 + 1

LINKS

Table of n, a(n) for n=3..16.

FORMULA

Step 1: Starting at the first prime number (3), convert to the minimum base (3, as all primes may be expressed in binary).

Step 2: If the next prime number can be converted into the same base using only 0 and 1 without exceeding the value of the next prime number in the next base, this is the next item in the sequence.

Step 3: If the next prime number cannot be expressed in this base before exceeding the value of the next prime number in the next base, skip this prime number and move on to the next prime number and repeat Step 2.

Step 4: If the next prime number cannot be expressed in this base before exceeding the value of the next prime number in the next base, but can be expressed in the next base, this is the next item in the sequence.

EXAMPLE

The first term is 3 in base 3. The next prime in that base is 13, which is greater than the value of the prime in the next base, which is 5 in base 4, so the second term is 5 in base 4.

CROSSREFS

A126359

Sequence in context: A004209 A162720 A112867 * A280105 A063697 A173198

Adjacent sequences:  A215508 A215509 A215510 * A215512 A215513 A215514

KEYWORD

nonn,base

AUTHOR

Jason Betts, Aug 14 2012.

STATUS

approved

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Last modified January 16 19:49 EST 2019. Contains 319206 sequences. (Running on oeis4.)