OFFSET
1,1
COMMENTS
The four polynomials considered in A139414 are 1373 - 146*n + 4*n^2, 1459 - 144*n + 4*n^2, 1301 - 142*n + 4*n^2, 1877 - 140*n + 4*n^2. For n=79 these are all composite: 14803, 15047, 15047, 15781.
An example of exactly 5 consecutive terms in the sequence: 4688-4692. An example of exactly 7 consecutive terms in the sequence: 14753-14759.
LINKS
Harry J. Smith, Table of n, a(n) for n = 1..10000
PROG
(PARI) p1(n)=4*n*n-146*n+1373 p2(n)=4*n*n-144*n+1459 p3(n)=4*n*n-142*n+1301 p4(n)=4*n*n-140*n+1877 { n=0; for (p=0, 45837, a1=p1(p); a2=p2(p); a3=p3(p); a4=p4(p); if (!isprime(a1) && !isprime(a2) && !isprime(a3) && !isprime(a4), n++; a=p; print(n, " ", a); write("b155814.txt", n, " ", a); ) ) } \\ Harry J. Smith, Jan 28 2009
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Jan 28 2009
EXTENSIONS
Edited by N. J. A. Sloane, Jan 29 2009
STATUS
approved