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A181837
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T(n,k) = [k is strongly prime to n], the indicator function of strong coprimality, triangle read by rows.
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1
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0, 0, 1, 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
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OFFSET
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0
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COMMENTS
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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.
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LINKS
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Table of n, a(n) for n=0..81.
Peter Luschny, Strong coprimality.
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EXAMPLE
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[n=0] 0
[n=1] 0, 1
[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.
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MAPLE
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A181837_triangle := proc(M) local strongCoprimes, triangle;
strongCoprimes := n -> select(k->igcd(k, n)=1, {$1..n})
minus numtheory[divisors](n-1):
triangle := proc(N, C) local T, L, k, n;
for n from 0 to N do
T := C(n); L := NULL;
for k from 0 to n do
L := L, `if`(member(k, T), 1, 0)
od;
print(L)
od end:
triangle(M, strongCoprimes) end:
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CROSSREFS
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Cf. A181830, A181831, A181832, A181838, A054431.
Sequence in context: A191153 A214210 A204547 * A185706 A188371 A188472
Adjacent sequences: A181834 A181835 A181836 * A181838 A181839 A181840
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KEYWORD
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nonn,tabl
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AUTHOR
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Peter Luschny, Nov 17 2010
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STATUS
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approved
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