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 A057045 Let R(i,j) be the rectangle with antidiagonals 1; 2,3; 4,5,6; ...; the n-th Lucas number is in antidiagonal a(n). 4
 2, 1, 2, 3, 4, 5, 6, 8, 10, 12, 16, 20, 25, 32, 41, 52, 66, 85, 107, 137, 174, 221, 281, 358, 455, 579, 737, 937, 1192, 1516, 1929, 2454, 3121, 3970, 5050, 6424, 8171, 10394, 13221, 16818, 21393, 27212 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Chai Wah Wu, Table of n, a(n) for n = 1..1000 FORMULA Round(sqrt(2*A000032(n-1))). - Vladeta Jovovic, Jun 14 2003 PROG (Python) from gmpy2 import isqrt_rem, lucas def A057045(n):     i, j = isqrt_rem(2*lucas(n-1))     return int(i + int(4*(j-i) >= 1)) # Chai Wah Wu, Aug 16 2016 CROSSREFS Cf. A057062, A057048, A022846, A057057, A057054. Sequence in context: A080915 A239484 A058714 * A237753 A058700 A220237 Adjacent sequences:  A057042 A057043 A057044 * A057046 A057047 A057048 KEYWORD nonn AUTHOR Clark Kimberling, Jul 30 2000 STATUS approved

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Last modified November 27 15:36 EST 2021. Contains 349394 sequences. (Running on oeis4.)