A319406 Write n-th prime in binary, then increase each run of 0's by one 0, and increase each run of 1's by one 1. a(n) is the decimal equivalent of the result.

12, 7, 51, 15, 103, 115, 195, 199, 207, 243, 63, 1587, 1635, 1639, 415, 1843, 487, 499, 775, 783, 3171, 799, 3271, 3299, 899, 3635, 911, 3687, 3699, 963, 255, 1543, 6243, 6247, 25395, 6351, 6387, 6535, 6543, 26227, 6599, 26419, 1663, 1795, 7219, 1807, 7367

Offset: 1

Author

N. J. A. Sloane, Sep 19 2018

Keywords

• nonn
• base

Comments

Apply A175046 to the primes.

Links

• Rémy Sigrist, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A175046.

A companion to A318923.

Programs

Python

from sympy import prime
def a(n):
    b = bin(prime(n))[2:]
    return int(b.replace("01", "001").replace("10", "110") + b[-1], 2)
print([a(n) for n in range(1, 48)]) # Michael S. Branicky, Dec 07 2021

Extensions

More terms from Rémy Sigrist, Sep 20 2018