A356421 Positive integers k such that k + p is a power of 2, where p is the least prime greater than k.
3, 15, 61, 255, 2043, 4093, 32765, 65535, 262141, 8388599, 33554397, 134217699, 268435453, 1073741821, 17179869159, 137438953463, 274877906937, 1099511627761, 8796093022179, 17592186044409, 70368744177649, 140737488355323, 281474976710635, 562949953421243
Offset: 1
Keywords
Examples
3 + 5 = 8; 15 + 17 = 32; 61 + 67 = 128.
Programs
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Python
from itertools import islice from sympy import nextprime def A356421_gen(): m = 1 while True: n = m+1<<1 k = m p = nextprime(k) while k+p>n: k -=1 p = nextprime(k) if k+p==n: yield k m = n-1 A356421_list = list(islice(A356421_gen(),30)) # Chai Wah Wu, Sep 11 2022
Extensions
Terms from Tom Duff via Seqfan.
Comments