Dennis Gruhlke has authored 2 sequences.
A350777
Numbers k where phi(k) divides k - 3.
Original entry on oeis.org
1, 2, 3, 9, 195, 5187, 1141967133868035, 3658018932844533311864835
Offset: 1
phi(195) = 96, 195 - 3 = 192, and 96 divides 192.
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Select[Range[6000], Divisible[#-3, EulerPhi[#]] &] (* Amiram Eldar, Jan 19 2022 *)
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isok(k) = !((k-3) % eulerphi(k)); \\ Michel Marcus, Jan 19 2022
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from sympy import totient
print("1, 2", end=", ")
for k in range (3, 10**8, 2):
if (k-3)%totient(k)==0:
print(k, end=", ", flush=True) # Martin Ehrenstein, Mar 26 2022
A348183
a(n) is the determinant of the n X n matrix M = (m_{i,j}), i,j from 0 to n-1: m{i,j} = (i+j)^2 mod n.
Original entry on oeis.org
1, 0, -1, -2, 0, 250, 5616, -33614, 0, 204073344, -900000000, -9431790764, 0, 10752962364222, -1870899108384768, -36328974609375000, 0, 22899384412078526344, -111400529859275793629184, -43843094862278417487512, 0, 2870507605405055660542502550, 67015802375208384199755038720
Offset: 0
a(2) = |0^2 mod 2, 1^2 mod 2| = -1
|1^2 mod 2, 2^2 mod 2|
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|0^2 mod 3, 1^2 mod 3, 2^2 mod 3|
a(3) = |1^2 mod 3, 2^2 mod 3, 3^2 mod 3| = -2
|2^2 mod 3, 3^2 mod 3, 4^2 mod 3|
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a[n_]:=Table[Mod[(i+j)^2,n],{i,0,n-1},{j,0,n-1}]; Join[{1},Table[Det[a[n]], {n, 22}]] (* Stefano Spezia, Oct 06 2021 *)
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a(n) = matdet(matrix(n, n, i, j, i--; j--; (i+j)^2 % n)); \\ Michel Marcus, Oct 06 2021
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from sympy import Matrix
def A348183(n): return Matrix(n,n,[pow(i+j,2,n) for i in range(n) for j in range(n)]).det() # Chai Wah Wu, Nov 24 2021
a(14)-a(17) corrected by and more terms from
Stefano Spezia, Oct 06 2021.
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