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 A087385 a(n) = smallest prime == 1 (mod T(n)) where T(n) is the n-th triangular number (A000217). 0
 2, 7, 7, 11, 31, 43, 29, 37, 181, 331, 67, 79, 547, 211, 241, 137, 307, 2053, 191, 211, 463, 1013, 277, 601, 1301, 3511, 379, 2437, 1741, 1861, 1489, 2113, 1123, 2381, 631, 1999, 4219, 1483, 2341, 821, 1723, 3613, 947, 991, 6211, 12973, 1129, 3529, 7351 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..49. EXAMPLE The prime corresponding to the triangular number 21 is 43. MATHEMATICA sm1[n_]:=Module[{p=NextPrime[n]}, While[Mod[p, n]!=1, p=NextPrime[p]]; p]; Join[ {2}, Table[sm1[(n(n+1))/2], {n, 2, 50}]] (* Harvey P. Dale, May 29 2020 *) CROSSREFS Sequence in context: A316352 A114532 A003061 * A168278 A267499 A351583 Adjacent sequences: A087382 A087383 A087384 * A087386 A087387 A087388 KEYWORD nonn AUTHOR Amarnath Murthy, Sep 09 2003 EXTENSIONS More terms from Sam Alexander, Dec 28 2003 STATUS approved

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Last modified August 9 05:47 EDT 2024. Contains 375027 sequences. (Running on oeis4.)