A243137 Primes encountered in A242902.

17, 23, 41, 43, 59, 61, 89, 113, 163, 179, 181, 239, 241, 257, 317, 379, 419, 421, 439, 499, 521, 523, 631, 733, 881, 883, 953, 1031, 1033, 1123, 1187, 1277, 1279, 1451, 1453, 1481, 1483, 1637, 1709, 1877, 1879, 1913, 2069, 2141, 2143, 2213, 2521, 2579, 2609, 2729, 2731

Offset

1,1

Comments

Preliminary analysis shows a higher %prime than the basic sequence of primes. The %prime is ~0.385 through the first 108K terms (excluding evens and multiples of 5). The PARI code is derived from the A242902 code supplied by Charles R Greathouse IV. This sequence is infinite if the twin primes are infinite.

Links

Table of n, a(n) for n=1..51.

Example

From A242902, (4+12)-1 is composite, (4+12+1) is prime so a(1)=17. Continuing, (6+18)-1 is prime, so a(2)=23, (6+18)+1 is composite. a(3)=41,a(4)=43.

Prog

(PARI)seq{v=[0, 4, 6]; p=11; pptr=0;
forprime(q=13, , if(q-p==2, v=[v[2], v[3], p+1];
if(isprime(v[1]+v[3]-1), pptr++; write("c:\\pari\\blist_sub.csv", pptr, " ,  ", v[1]+v[3]-1) );
if(isprime(v[1]+v[3]+1), pptr++; write("c:\\pari\\blist_sub.csv", pptr, " ,  ", v[1]+v[3]+1) )
); p=q ; if(pptr>10000, break)  ) }

Crossrefs

Cf. A242902.

Sequence in context: A241528 A156567 A231332 * A256397 A139843 A151953

Adjacent sequences: A243134 A243135 A243136 * A243138 A243139 A243140

Keyword

easy,nonn

Author

Bill McEachen, Jun 01 2014

Status

approved