login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A330428
Smallest prime p such that both nearest primes up and down are farther away than n*log(p).
4
5, 211, 38501, 413353, 10938023, 142414669, 163710121, 8835528511, 31587561361, 343834606051, 1480975873513, 26923643849953
OFFSET
1,1
COMMENTS
For these numbers, the name "Lowest Frogger Primes" LFP(n) is suggested because (frog) jumps with a length greater than n times the local average are required to bridge the gaps (logs).
PROG
(PARI) {my(npp=2, np=3, n=1); forprime(p=5, 10^9, my(d=log(p)*n); if(np-npp>d&&p-np>d, print(np, ", "); n++); npp=np; np=p)} \\ Hugo Pfoertner, Dec 14 2019
CROSSREFS
Cf. A288908 (with 1*log(P)), A330426 (with 2*log(P)), A330427 (with 3*log(P)).
Sequence in context: A203470 A165208 A293652 * A048433 A270870 A144796
KEYWORD
nonn,more,hard
AUTHOR
Steven M. Altschuld, Dec 14 2019
EXTENSIONS
a(5)-a(9) from Hugo Pfoertner, Dec 14 2019
a(10) from Hugo Pfoertner, Dec 16 2019
a(11)-a(12) from Giovanni Resta, Dec 19 2019
STATUS
approved