A078454 Index of the first occurrence of prime(n) in A060324.

1, 3, 7, 13, 37, 31, 89, 51, 101, 219, 309, 973, 146, 832, 464, 1031, 2714, 2352, 6403, 311, 6397, 6352, 1487, 1439, 20718, 4252, 11958, 3719, 1332, 4136, 14509, 4601, 4223, 12414, 4043, 38862, 57949, 20257, 4958, 4832, 2213, 96792, 27932, 261337

Offset: 1

Author

Amarnath Murthy, Dec 23 2002

Keywords

• nonn

Comments

Smallest k such that k*prime(n) + k - 1 is a prime.

Links

• Franklin T. Adams-Watters, Table of n, a(n) for n = 1..100

Crossrefs

Cf. A060324.

Programs

PARI

A060324(n)=forprime(q=2,999999999,if(isprime(n*(q+1)-1),return(q)));-1
al(n)=local(v,k,xv);v=vector(n);while(n>0,xv=primepi(A060324(k++));if(xv<=#v&v[xv]==0,v[xv]=k;n--));v (End)

Extensions

More terms from Franklin T. Adams-Watters, May 25 2010