id:A056106 - OEIS Search Results

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Second spoke of a hexagonal spiral.

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9

1, 3, 11, 25, 45, 71, 103, 141, 185, 235, 291, 353, 421, 495, 575, 661, 753, 851, 955, 1065, 1181, 1303, 1431, 1565, 1705, 1851, 2003, 2161, 2325, 2495, 2671, 2853, 3041, 3235, 3435, 3641, 3853, 4071, 4295, 4525, 4761, 5003, 5251, 5505, 5765, 6031, 6303 (list; graph; listen)

	OFFSET	`0,2`
	COMMENT	`a(n) = A096777(3*n) for n>0. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Dec 29 2007`
	LINKS	`H. Bottomley, Illustration of initial terms` `G. Nebe and N. J. A. Sloane, Home page for hexagonal (or triangular) lattice A2`
	FORMULA	`a(n) = 3n^2-n+1 = a(n-1)+6n-4 = 2a(n-1)-a(n-2)+6 = 3a(n-1)-3a(n-2)+a(n-3) = A056105(n)+n = A056107(n)-n = A056108(n)-2n = A056109(n)-3n = A003215(n)-4n` `E.g.f.: (1+2x+3x^2)exp(x). - Paul Barry (pbarry(AT)wit.ie), Mar 13 2003`
	CROSSREFS	`Cf. A054552 for example of square (or octagonal) spiral spoke.` `Adjacent sequences: A056103 A056104 A056105 this_sequence A056107 A056108 A056109` `Sequence in context: A141595 A112051 A118436 this_sequence A129082 A060746 A111935`
	KEYWORD	`easy,nonn`
	AUTHOR	`Henry Bottomley (se16(AT)btinternet.com), Jun 09 2000`

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Last modified October 10 20:39 EDT 2008. Contains 144831 sequences.

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