OFFSET
1,3
PROG
(PARI)
isA369251(n) = if(3!=(n%4), 0, my(v = [3, 3], ip = #v, r); while(1, r = (n-(v[1]*v[2])) / (v[1]+v[2]); if(r < v[2], ip--, ip = #v; if(1==denominator(r) && isprime(r), return(1))); if(!ip, return(0)); v[ip] = nextprime(1+v[ip]); for(i=1+ip, #v, v[i]=v[i-1])));
isA369464(n) = !isA369251(n);
CROSSREFS
Positions of 0's in A369054.
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jan 24 2024
STATUS
approved