OFFSET
0,1
COMMENTS
If a(n) == 0 (mod 12), then a(n+1) = a(n)/12.
Records: 5, 18, 39, 182, 262, 549, 752, 811, 1456, ..., .
Corresponding primes are twin primes for n = 0, 1, 2, 5, 15, 26, 28, 55, 72, ..., .
LINKS
Robert G. Wilson v, Table of n, a(n) for n = 0..200
MATHEMATICA
f[n_] := Block[{k = 1, j = 12^n/2}, While[ h = k*j; PrimeQ@h || NextPrime[h, -1] + NextPrime@h != 2 h, k++ ]; k]; Array[f, 80, 0]
PROG
(Python)
from sympy import nextprime, prevprime
def sum2succ(n): return n == prevprime(n//2) + nextprime(n//2)
def a(n):
if n == 0: return 5
k, pow12 = 1, 12**n
while not sum2succ(k*pow12): k += 1
return k
print([a(n) for n in range(67)]) # Michael S. Branicky, May 01 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov & Robert G. Wilson v, Aug 15 2010
STATUS
approved