A375793 Numbers m such that 2^m == 2 (mod m-th triangular number).
1, 3, 5, 11, 13, 29, 37, 61, 73, 131, 157, 181, 193, 277, 313, 397, 421, 457, 541, 561, 613, 661, 673, 733, 757, 877, 997, 1093, 1153, 1201, 1213, 1237, 1289, 1321, 1381, 1453, 1621, 1657, 1753, 1873, 1905, 1933, 1993, 2017, 2137, 2341, 2473, 2557, 2593, 2797, 2857, 2917, 3061, 3217, 3253, 3313, 3389, 3457
Offset: 1
Keywords
Links
- Alois P. Heinz, Table of n, a(n) for n = 1..10000
Programs
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Magma
[1] cat [m: m in [2..3500] | Modexp(2, m, m*(m+1) div 2) eq 2];
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Maple
t:= n-> n*(n+1)/2: q:= m-> is(2&^m-2 mod t(m)=0): select(q, [$1..3457])[]; # Alois P. Heinz, Sep 21 2024
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Mathematica
Select[Range[3457],Mod[2^#-2,#(#+1)/2 ]==0&] (* James C. McMahon, Sep 23 2024 *)
Comments