OFFSET
1,1
COMMENTS
Are all terms prime numbers?
a(9) <= 14567138141, a(10) <= 5509396663871, a(11) <= 4128894057139, a(12) <= 13264466350165447, a(13) <= 6115610326638653. - Daniel Suteu, Mar 14 2022
EXAMPLE
a(2) = 97 because omega(97) = (omega(2*97 + 1) - 1)/2 = (omega(3*5*13) - 1)/2 = 1.
MATHEMATICA
a[n_] := Module[{k = 2}, While[PrimeNu[k] != (PrimeNu[n*k + 1] - 1)/n, k++]; k]; Array[a, 5] (* Amiram Eldar, Mar 09 2022 *)
PROG
(PARI) a(n) = my(k=2); while (omega(k) != (omega(n*k + 1) - 1)/n, k++); k; \\ Michel Marcus, Mar 09 2022
(Python)
from sympy import factorint
for n in range(1, 8):
for k in range(2, 10**10):
if len(factorint(k).keys())*n+1==len(factorint(k*n+1).keys()):
print(n, k)
break # Martin Ehrenstein, Mar 14 2022
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Juri-Stepan Gerasimov, Mar 09 2022
EXTENSIONS
a(8) from Martin Ehrenstein, Mar 14 2022
STATUS
approved