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A181837
T(n,k) = [k is strongly prime to n], the indicator function of strong coprimality, triangle read by rows.
2
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0
OFFSET
0
COMMENTS
k is strongly prime to n iff k is relatively prime to n and k does not divide n-1.
T(n,k) = [k is strong prime to n] where [] denotes the Iverson bracket.
EXAMPLE
[n=0] 0
[n=1] 0, 0
[n=2] 0, 0, 0
[n=3] 0, 0, 0, 0
[n=4] 0, 0, 0, 0, 0
[n=5] 0, 0, 0, 1, 0, 0
Let n = 5 then the numbers prime to n are {1, 2, 3, 4} and the positive divisors of n-1 are {1, 2, 4}. Thus only 3 is strong prime to 5.
PROG
(SageMath)
def isstrongprimeto(k, n): return not(k.divides(n - 1)) and gcd(k, n) == 1
for n in srange(12): print([int(isstrongprimeto(k, n)) for k in srange(n+1)])
# Peter Luschny, Dec 03 2023
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Peter Luschny, Nov 17 2010
EXTENSIONS
Corrected T(1, 1) to 0 by Peter Luschny, Dec 03 2023
STATUS
approved