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 A161550 Largest prime <= n^2+n. 2
 2, 5, 11, 19, 29, 41, 53, 71, 89, 109, 131, 151, 181, 199, 239, 271, 293, 337, 379, 419, 461, 503, 547, 599, 647, 701, 751, 811, 863, 929, 991, 1051, 1117, 1187, 1259, 1327, 1399, 1481, 1559, 1637, 1721, 1801, 1889, 1979, 2069, 2161, 2251, 2351, 2447, 2549, 2647 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Nathaniel Johnston, Table of n, a(n) for n = 1..10000 MAPLE A161550 := proc(n) return prevprime(n*(n+1)+1): end: seq(A161550(n), n=1..51); # Nathaniel Johnston, May 01 2011 MATHEMATICA PrimePrev[n_]:=Module[{k}, k=n-1; While[ !PrimeQ[k], k-- ]; k]; lst={}; Do[a=n^2+n; p=PrimePrev[a]; AppendTo[lst, p], {n, 2, 5!}]; lst (* Vladimir Joseph Stephan Orlovsky, Jun 13 2009 *) Join[{2}, Table[NextPrime[n^2+n, -1], {n, 2, 60}]] (* Harvey P. Dale, May 01 2011 *) PROG (PARI) a(n)=precprime(n^2+n) \\ Charles R Greathouse IV, Mar 27 2014 CROSSREFS Sequence in context: A152471 A088796 A190309 * A245207 A215762 A085626 Adjacent sequences:  A161547 A161548 A161549 * A161551 A161552 A161553 KEYWORD easy,nonn AUTHOR Daniel Tisdale, Jun 13 2009 EXTENSIONS More terms from Vladimir Joseph Stephan Orlovsky, Jun 13 2009 STATUS approved

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Last modified August 18 08:57 EDT 2019. Contains 326077 sequences. (Running on oeis4.)