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A047873 a(n) = max_{r=1..n-1} ceiling(t(t(n)-t(r-1))/(n-r+1)), where t() = triangular numbers A000217. 1
1, 3, 8, 15, 27, 43, 65, 94, 130, 175, 229, 294, 369, 456, 557, 671, 800, 944, 1105, 1283, 1479, 1695, 1930, 2187, 2465, 2765, 3090, 3439, 3813, 4213, 4641, 5096, 5580, 6095, 6639, 7216, 7825, 8466, 9143, 9855 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Another lower bound for Honaker triangle problem (A047837); conjectured to be exact value.

LINKS

Table of n, a(n) for n=1..40.

FORMULA

Empirical g.f.: -x*(x^15 - 3*x^14 + 3*x^13 - 5*x^12 + 5*x^11 - 9*x^10 + 7*x^9 - 10*x^8 + 7*x^7 - 9*x^6 + 5*x^5 - 6*x^4 + 2*x^3 - 3*x^2 - 1) / ((x-1)^4*(x^2-x+1)*(x^2+1)*(x^2+x+1)^2*(x^4-x^2+1)). [Colin Barker, Jan 18 2013]

CROSSREFS

Cf. A047837, A047866.

Sequence in context: A081276 A210979 A047837 * A036419 A054107 A031125

Adjacent sequences:  A047870 A047871 A047872 * A047874 A047875 A047876

KEYWORD

easy,nonn

AUTHOR

Mike Keith (domnei(AT)aol.com)

STATUS

approved

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Last modified November 18 07:22 EST 2019. Contains 329252 sequences. (Running on oeis4.)