

A249011


Smallest prime(i) such that the constellation of the n following prime gaps is the same constellation as the gaps following prime(i+n).


2




OFFSET

1,1


COMMENTS

"Constellation" in the title means that not only the set of the prime gaps after the two primes is the same, but the order of the prime gaps must also be preserved.


LINKS



EXAMPLE

a(1)=3 as the prime gap [2] is repeated in the same order for 3>5 and 5>7.
a(2)=5 as the prime gaps [2, 4] are repeated for 5>7>11 and 11>13>17.
a(4)=839 as the prime gaps [14, 4, 2, 4] are repeated for the 2 consecutive sets of consecutive primes 839>853>857>859>863 and 863>877>881>883>887.


PROG

(PARI) findspg(n, vpg) = {for (k=1, #vpg2*n, pga = vector(n, i, vpg[k+i1]); pgb = vector(n, i, vpg[k+n+i1]); if (pga==pgb, return (k)); ); }
lista(nn=6, pp=10000000) = {vp = primes(pp); vpg = vector(pp1, i, vp[i+1]  vp[i]); for (n=1, nn, ip = findspg(n, vpg); if (ip>0, print1(prime(ip), ", ")); ); } \\ Michel Marcus, Oct 25 2014


CROSSREFS

Cf. A001223 (prime gaps), A249012 (order of the prime gaps not considered).


KEYWORD

nonn,more


AUTHOR



STATUS

approved



