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A376557
Triangle read by rows: the n-th row gives the least sequence of n consecutive numbers with the same number of divisors.
0
1, 2, 3, 33, 34, 35, 242, 243, 244, 245, 11605, 11606, 11607, 11608, 11609, 28374, 28375, 28376, 28377, 28378, 28379, 171893, 171894, 171895, 171896, 171897, 171898, 171899, 1043710445721, 1043710445722, 1043710445723, 1043710445724, 1043710445725, 1043710445726, 1043710445727, 1043710445728
OFFSET
1,2
COMMENTS
Inspired by the 4th row given by Guy.
REFERENCES
R. K. Guy, Unsolved Problems in Number Theory, Springer, 1st edition, 1981. See section B18.
EXAMPLE
The triangle begins as:
1;
2, 3;
33, 34, 35;
242, 243, 244, 245;
11605, 11606, 11607, 11608, 11609;
28374, 28375, 28376, 28377, 28378, 28379;
171893, 171894, 171895, 171896, 171897, 171898, 171899;
...
MATHEMATICA
row[n_]:=Module[{}, k=1; nd=DivisorSigma[0, k]; While[Product[Boole[DivisorSigma[0, k+i]==nd], {i, n-1}]!=1, k++; nd=DivisorSigma[0, k]]; Table[i+k, {i, 0, n-1}]]; Array[row, 7]//Flatten
CROSSREFS
Cf. A000005, A006558 (1st column), A019273 (right diagonal), A039665.
Sequence in context: A079883 A358041 A066269 * A083785 A046487 A062922
KEYWORD
nonn,tabl
AUTHOR
Stefano Spezia, Sep 28 2024
STATUS
approved