A182217 - OEIS

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A182217

Primes p = prime(n) such that there is k>0 for which prime(n+k) = prime(n) + 4^(k-1).

2, 3, 43, 73, 151, 157, 163, 181, 277, 337, 367, 373, 433, 487, 601, 631, 643, 727, 757, 811, 823, 937, 967, 1093, 1213, 1471, 1483, 1543, 1567, 1693, 1873, 2083, 2137, 2281, 2341, 2383, 2647, 2671, 2953, 3307, 3313, 3517, 3607, 3847, 4003, 4441, 4447

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Table of n, a(n) for n=1..47.

EXAMPLE

2=prime(1+1)-4^(1-1)=3-1, 3=prime(2+2)-4^(2-1)=7-4, 43=prime(14+3)-4^(3-1)=59-16, 73=prime(21+3)-4^(3-1)=89-16.

PROG

(PARI) is_A182217(p)={isprime(p) || return; my(q=p); for(k=0, 9, p+4^k==(q=nextprime(q+1)) & return(1))} \\ M. F. Hasler, May 20 2012

(PARI) for(n=1, 9999, for(k=1, 9, prime(n+k)-prime(n)==4^(k-1)&!print1(prime(n)", ")&break)) \\ M. F. Hasler, May 20 2012

CROSSREFS

Cf. A001223.