OFFSET
1,5
COMMENTS
For any m > 0:
- let F(m) be the set of distinct Fermi-Dirac primes (A050376) with product m,
- for any i >=0 0 and j >= 0, let f(prime(i+1)^(2^i)) be the lattice point with coordinates X=i and Y=j (where prime(k) denotes the k-th prime number),
- f establishes a bijection from the Fermi-Dirac primes to the lattice points with nonnegative coordinates,
- let P(m) = { f(p) | p in F(m) },
- P establishes a bijection from the nonnegative integers to the set, say L, of finite sets of lattice points with nonnegative coordinates,
- let Q be the inverse of P,
- for any n > 0 and k > 0:
T(n, k) = Q(P(n) + P(k))
where "+" denotes the Minkowski addition on L.
This sequence has similarities with A297845, and their data sections almost match; T(6, 6) = 30, however A297845(6, 6) = 90.
This sequence has similarities with A067138; here we work on dimension 2, there in dimension 1.
LINKS
Rémy Sigrist, PARI program for A306697
OEIS Wiki, "Fermi-Dirac representation" of n
Eric Weisstein's World of Mathematics, Distributive
Wikipedia, Minkowski addition
FORMULA
For any m > 0, n > 0, k > 0, i >= 0, j >= 0:
- T(n, k) = T(k, n) (T is commutative),
- T(m, T(n, k)) = T(T(m, n), k) (T is associative),
- T(n, 1) = 1 (1 is an absorbing element for T),
- T(n, 2) = n (2 is an identity element for T),
- T(n, 3) = A003961(n),
- T(n, 4) = n^2 (A000290),
- T(n, 5) = A357852(n),
- T(n, 7) = A045968(n) (when n > 1),
- T(n, 11) = A045970(n) (when n > 1),
- T(n, 2^(2^i)) = n^(2^i),
- T(2^i, 2^j) = 2^A067138(i, j),
- T(2^(2^i), 2^(2^j)) = 2^(2^(i + j)),
From Peter Munn, Dec 05 2019:(Start)
Equivalently, T(prime(i_1 - 1)^(2^(j_1)), prime(i_2 - 1)^(2^(j_2))) = prime(i_1+i_2 - 1)^(2^(j_1+j_2)), where prime(i) = A000040(i).
(End)
EXAMPLE
Array T(n, k) begins:
n\k| 1 2 3 4 5 6 7 8 9 10 11 12
---+-------------------------------------------------------------
1| 1 1 1 1 1 1 1 1 1 1 1 1
2| 1 2 3 4 5 6 7 8 9 10 11 12
3| 1 3 5 9 7 15 11 27 25 21 13 45
4| 1 4 9 16 25 36 49 64 81 100 121 144
5| 1 5 7 25 11 35 13 125 49 55 17 175
6| 1 6 15 36 35 30 77 216 225 210 143 540
7| 1 7 11 49 13 77 17 343 121 91 19 539
8| 1 8 27 64 125 216 343 128 729 1000 1331 1728
9| 1 9 25 81 49 225 121 729 625 441 169 2025
10| 1 10 21 100 55 210 91 1000 441 110 187 2100
11| 1 11 13 121 17 143 19 1331 169 187 23 1573
12| 1 12 45 144 175 540 539 1728 2025 2100 1573 720
PROG
(PARI) \\ See Links section.
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Rémy Sigrist, Mar 05 2019
STATUS
editing