%I #28 Sep 11 2022 10:31:08
%S 3,15,61,255,2043,4093,32765,65535,262141,8388599,33554397,134217699,
%T 268435453,1073741821,17179869159,137438953463,274877906937,
%U 1099511627761,8796093022179,17592186044409,70368744177649,140737488355323,281474976710635,562949953421243
%N Positive integers k such that k + p is a power of 2, where p is the least prime greater than k.
%C The corresponding sequence of primes is the intersection of A014210 and A356434 without the initial 2.
%e 3 + 5 = 8;
%e 15 + 17 = 32;
%e 61 + 67 = 128.
%o (Python)
%o from itertools import islice
%o from sympy import nextprime
%o def A356421_gen():
%o m = 1
%o while True:
%o n = m+1<<1
%o k = m
%o p = nextprime(k)
%o while k+p>n:
%o k -=1
%o p = nextprime(k)
%o if k+p==n:
%o yield k
%o m = n-1
%o A356421_list = list(islice(A356421_gen(),30)) # _Chai Wah Wu_, Sep 11 2022
%Y Cf. A000040, A000079, A014210, A356434.
%K nonn
%O 1,1
%A _Ali Sada_, Aug 06 2022
%E Terms from _Tom Duff_ via Seqfan.