id:A053631 - OEIS Search Results

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Pythagorean spiral: a(n-1)+1, a(n) and a(n)+1 are the sides of a right angled triangle (a primitive Pythagorean triangle).

+0
2

2, 4, 12, 84, 3612, 6526884, 21300113901612, 226847426110843688722000884, 25729877366557343481074291996721923093306518970391612 (list; graph; listen)

	OFFSET	`1,1`
	FORMULA	`a(1)=2; for n>=2: a(n) = a(n-1) + a(n-1)^2/2 = A046092(a(n-1)/2)`
	CROSSREFS	`Cf. A046092.` `Sequence in context: A001206 A144295 A119489 this_sequence A120618 A038791 A001696` `Adjacent sequences: A053628 A053629 A053630 this_sequence A053632 A053633 A053634`
	KEYWORD	`nonn`
	AUTHOR	`Henry Bottomley (se16(AT)btinternet.com), Mar 21 2000`
	EXTENSIONS	`Corrected and extended by James A. Sellers (sellersj(AT)math.psu.edu), Mar 22 2000.` `a(1) = 2 added by Zak Seidov, Apr 10 2007`

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Last modified November 22 20:51 EST 2009. Contains 167312 sequences.

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