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URL: https://oeis.org/A391357

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A391357
Rectangular array R read by falling antidiagonals: R(n,k) = prime(n) + prime(n+k).
2
5, 7, 8, 9, 10, 12, 13, 14, 16, 18, 15, 16, 18, 20, 24, 19, 20, 22, 24, 28, 30, 21, 22, 24, 26, 30, 32, 36, 25, 26, 28, 30, 34, 36, 40, 42, 31, 32, 34, 36, 40, 42, 46, 48, 52, 33, 34, 36, 38, 42, 44, 48, 50, 54, 60, 39, 40, 42, 44, 48, 50, 54, 56, 60, 66, 68
OFFSET
1,1
FORMULA
R(n,k) = prime(n) + prime(n+k).
Transpose of the array in A391358.
EXAMPLE
Corner:
5 7 9 13 15 19 21 25 31 33
8 10 14 16 20 22 26 32 34 40
12 16 18 22 24 28 34 36 42 46
18 20 24 26 30 36 38 44 48 50
24 28 30 34 40 42 48 52 54 58
30 32 36 42 44 50 54 56 60 66
36 40 46 48 54 58 60 64 70 76
42 48 50 56 60 62 66 72 78 80
52 54 60 64 66 70 76 82 84 90
60 66 70 72 76 82 88 90 96 100
MATHEMATICA
z = 12; p[n_] := Prime[n];
s[n_] := Table[p[n] + p[n + k], {k, 1, z}];
t = Table[s[n], {n, 1, z}]
Grid[t] (* array *)
u[n_, k_] := s[n][[k]];
Table[u[n - k + 1, k], {n, 12}, {k, n, 1, -1}] // Flatten (* sequence *)
CROSSREFS
Cf. A052147 (row 1), A113935 (row 2), A175222 (row 3), A175223 (row 4), A001043 (column 1), A048448 (column 2), A092390 (main diagonal), A391358 (transpose), A391359.
Sequence in context: A038609 A078892 A370090 * A164374 A072281 A242273
KEYWORD
nonn,tabl,easy
AUTHOR
Clark Kimberling, Dec 18 2025
STATUS
approved