id:A118375 - OEIS Search Results

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Minimum over all permutations b of 1..n of sum b(i)*b^{-1}(i).

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1, 5, 11, 20, 35, 57, 85, 120, 165, 221, 287, 364, 455, 561, 681, 816, 969, 1141, 1331, 1540, 1771, 2025, 2301, 2600, 2925, 3277, 3655, 4060, 4495, 4961, 5457, 5984, 6545, 7141, 7771, 8436, 9139, 9881, 10661, 11480, 12341, 13245, 14191, 15180, 16215 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`The maximum obtainable is A000330, the square pyramidal numbers. Problem suggested by Leroy Quet.`
	LINKS	`Leroy Quet, Home Page (listed in lieu of email address)` `sci.math thread.`
	FORMULA	`a(n) = T(n) + e(n), where T(n) = n(n+1)(n+2)/6 = A000292(n) is the tetrahedal numbers and e(n) = 0 if n = 0,1 (mod 4) and 1 if n = 2,3 (mod 4). (Published by Rob Johnson in sci.math.)`
	CROSSREFS	`Cf. A000292, A000330.` `Sequence in context: A032527 A026038 A080957 this_sequence A099400 A139534 A166480` `Adjacent sequences: A118372 A118373 A118374 this_sequence A118376 A118377 A118378`
	KEYWORD	`nonn`
	AUTHOR	`Frank Adams-Watters (FrankTAW(AT)Netscape.net), May 15 2006`

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Last modified December 8 08:31 EST 2009. Contains 170430 sequences.

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