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A098377 Left edge T(n,n) or the main diagonal of the triangle A097883. 1
1, 3, 4, 11, 12, 25, 22, 39, 40, 57, 58, 89, 78, 115, 112, 141, 142, 183, 182, 225, 226, 269, 252, 319, 312, 365, 364, 423, 422, 487, 474, 559, 534, 629, 600, 701, 680, 759, 758, 849, 842, 935, 912, 1025, 1008, 1117, 1100, 1203, 1190, 1311, 1300, 1419, 1400 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..52.

FORMULA

a(n) = A097883(t) where t is a triangular number.

MATHEMATICA

a[0, 0] = 1; a[m_, n_] := a[m, n] = Block[{p = Sort[ Flatten[ Join[ Table[ a[i, j], {i, 0, m - 1}, {j, 0, i}], Table[ a[i, j], {i, m, m}, {j, 0, n - 1}]] ]]}, k = Complement[ Range[ p[[ -1]] + 1], p][[1]]; While[ Position[p, k] != {} || If[n == 0, GCD[k, a[m - 1, 0]] != 1, If[n == m, GCD[k, a[m - 1, m - 1]] != 1, GCD[k, a[m - 1, n]] != 1 || GCD[k, a[m - 1, n - 1]] != 1]], k++ ]; k]; Table[ a[m, m], {m, 0, 52}]

CROSSREFS

Cf. A097883, A098376.

Sequence in context: A228236 A047457 A226632 * A075646 A133621 A216558

Adjacent sequences:  A098374 A098375 A098376 * A098378 A098379 A098380

KEYWORD

nonn

AUTHOR

Leroy Quet and Robert G. Wilson v, Sep 04 2004

STATUS

approved

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Last modified February 17 15:19 EST 2019. Contains 320220 sequences. (Running on oeis4.)