A337122 a(n) is the smallest positive integer k for which the mod-k Collatz orbit has the same length as the ordinary Collatz orbit.
5, 4, 17, 5, 17, 17, 53, 9, 53, 17, 53, 17, 17, 53, 59, 17, 53, 53, 74, 17, 18, 53, 59, 25, 61, 34, 1829, 53, 74, 59, 1829, 27, 101, 53, 44, 53, 93, 74, 225, 17, 1829, 18, 163, 53, 57, 59, 1829, 39, 77, 61, 95, 53, 34, 1829, 1829, 57, 197, 74, 225, 89
Offset: 1
Keywords
Links
- Markus Sigg, Table of n, a(n) for n = 1..10000
Crossrefs
Cf. A294643.
Programs
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PARI
orbitSize(n, k) = { my(S = Set([])); if (k, n = n % k); while(!setsearch(S, n), S = setunion(S, Set([n])); n = if(n % 2, 3*n+1, n/2); if(k, n = n % k);); return(#S); }; a(n) = { my(o = orbitSize(n, 0), k); for(k = 1, oo, if(orbitSize(n, k) == o, return(k))); }; makeVec(m) = { my(v = [], n); for(n = 1, m, v = concat(v, a(n))); return(v); }; makeVec(60)
Comments