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A309839 a(n) = GAP_n: first integer m that is not the dimension of a semisimple subalgebra of M_n(k). 2
3, 6, 7, 12, 15, 22, 23, 42, 43, 48, 63, 76, 79, 96, 115, 140, 143, 166, 167, 192, 247, 248, 279, 312, 347, 384, 423, 472, 483, 526, 527, 572, 619, 624, 719, 724, 827, 832, 889, 948, 1009, 1072, 1087, 1152, 1219, 1288, 1359, 1432, 1507, 1520, 1597, 1676, 1679 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

COMMENTS

Define the sequence a(n) = GAP_n to be the smallest integer that is not the dimension of a semisimple subalgebra of M_n(k). This is one more than the upper endpoint of the continuous region of M_n(k). Because when n = 1 there are no gaps, this sequence begins at n = 2. See Heikoop paper, page 31.

LINKS

Michael De Vlieger, Table of n, a(n) for n = 2..101

Phillip Tomas Heikoop, Dimensions of Matrix Subalgebras, Bachelor's Thesis, Worcester Polytechnic Institute (2019).

Phillip Heikoop, C++11 code to generate the sequence

FORMULA

a(n) > n^2 - 4 * sqrt(n + 2).

CROSSREFS

Cf. A000124, A002620, A069999, A138544, A309838.

Sequence in context: A163617 A189634 A047705 * A169799 A069891 A190118

Adjacent sequences:  A309836 A309837 A309838 * A309840 A309841 A309842

KEYWORD

nonn

AUTHOR

Phillip Heikoop, Aug 19 2019

STATUS

approved

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Last modified December 10 14:27 EST 2019. Contains 329896 sequences. (Running on oeis4.)