OFFSET
1,1
COMMENTS
Note interesting patterns in the graph. - Zak Seidov, Dec 13 2011
LINKS
Zak Seidov, Table of n, a(n) for n = 1..10000
EXAMPLE
5 is the smallest prime of the form 1+4m, 17 is the smallest prime of the form 1+8m, 13 is the smallest prime of the form 1+12m, etc. - Zak Seidov, Dec 13 2011
MATHEMATICA
nn=100; Reap[Do[p=1+4n; While[!PrimeQ[p], p=p+4n]; Sow[p], {n, nn}]][[2, 1]] (* Zak Seidov, Dec 13 2011 *)
PROG
(PARI) for(n=1, 80, s=1; while((isprime(s)*s-1)%(4*n)>0, s++); print1(s, ", "))
(PARI) nn=10000; for(n=1, nn, s=1+4*n; while(!isprime(s), s=s+4*n); print1(s, ", ")) \\ Zak Seidov, Dec 13 2011
(Python)
from sympy import isprime
def a(n):
k = 4*n + 1
while not isprime(k): k += 4*n
return k
print([a(n) for n in range(1, 56)]) # Michael S. Branicky, May 17 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, May 15 2002
EXTENSIONS
More terms from Benoit Cloitre, May 18 2002
STATUS
approved