A084715 Smallest number of the form n*k + 1 that is divisible by all the phi(n) numbers less than n and relatively prime to n.
3, 4, 9, 36, 25, 120, 105, 280, 441, 2520, 385, 277200, 70785, 56056, 585585, 5045040, 1446445, 183783600, 8729721, 40646320, 1322685, 4655851200, 37182145, 1070845776, 900951975, 5949143200, 6453758025, 80313433200, 215656441
Offset: 2
Keywords
Examples
a(9) = 280= 31*9 +1 is divisible by 1,2,4,5,7 and 8.
Crossrefs
Cf. A038610.
Programs
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PARI
for (i = 2, 50, g = 1; for (j = 2, i - 1, if (gcd(i, j) == 1, g = lcm(g, j))); print1(lift(chinese(Mod(1, i), Mod(0, g))), ", ")); \\ David Wasserman, Jan 03 2005
Extensions
More terms from David Wasserman, Jan 03 2005