A384376 Irregular triangle read by rows: T(n,k) is the number of connected induced k-vertex subgraphs of the 1-skeleton of the n-th Johnson solid, up to symmetries of that solid; 1 <= n <= 92, 1 <= k <= A242733(n).
2, 2, 3, 2, 1, 2, 2, 3, 3, 2, 1, 2, 4, 6, 10, 14, 15, 8, 2, 1, 2, 4, 6, 13, 21, 37, 47, 51, 28, 12, 2, 1, 2, 4, 6, 13, 25, 49, 86, 136, 177, 174, 118, 47, 14, 2, 1, 3, 5, 9, 18, 39, 79, 168, 335, 646, 1147, 1843, 2548, 2908, 2420, 1300, 473, 121, 24, 3, 1, 3, 4, 6, 7, 6, 3, 1
Offset: 1
Examples
Triangle begins: n\k| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 ---+------------------------------------------------------------------------------ 1 | 2 2 3 2 1 2 | 2 2 3 3 2 1 3 | 2 4 6 10 14 15 8 2 1 4 | 2 4 6 13 21 37 47 51 28 12 2 1 5 | 2 4 6 13 25 49 86 136 177 174 118 47 14 2 1 6 | 3 5 9 18 39 79 168 335 646 1147 1843 2548 2908 2420 1300 473 121 24 3 1 7 | 3 4 6 7 6 3 1 8 | 3 4 7 12 17 16 9 3 1 9 | 3 4 7 13 24 35 36 22 9 3 1 10 | 3 4 9 16 21 16 8 3 1 11 | 3 4 9 18 36 49 41 23 9 3 1 12 | 2 2 3 2 1 13 | 2 2 4 5 4 2 1 14 | 2 3 4 7 6 6 2 1 15 | 2 3 5 10 15 20 13 8 2 1 16 | 2 3 5 11 20 38 41 36 16 8 2 1 17 | 2 3 6 13 19 21 12 7 2 1 18 | 3 7 12 29 60 134 255 425 523 420 223 80 21 3 1 19 | 3 7 12 32 69 174 393 899 1856 3512 5517 6874 6173 3964 1789 615 146 30 3 1
Links
- Pontus von Brömssen, Table of n, a(n) for n = 1..638 (first 39 rows)
- Eric Weisstein's World of Mathematics, Johnson Solid.
- Wikipedia, List of Johnson solids.
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