A153780 - OEIS

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A153780

10 times pentagonal numbers: 5n(3n-1).

0, 10, 50, 120, 220, 350, 510, 700, 920, 1170, 1450, 1760, 2100, 2470, 2870, 3300, 3760, 4250, 4770, 5320, 5900, 6510, 7150, 7820, 8520, 9250, 10010, 10800, 11620, 12470, 13350, 14260, 15200, 16170, 17170, 18200, 19260, 20350 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,2`
	FORMULA	`a(n) = 15n^2 - 5n = A000326(n)10 = A049450(n)5 = A152734(n)2.` `a(n)=30n+a(n-1)-20 (with a(0)=0) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Aug 03 2010]`
	EXAMPLE	`a(1)=301+0-20=10; a(2)=302+10-20=50; a(3)=30*3+50-20=120 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Aug 03 2010]`
	CROSSREFS	`Cf. A000326, A049450, A152734, A152996, A153449.` `Sequence in context: A036786 A085444 A102915 * A196507 A008531 A051230` `Adjacent sequences: A153777 A153778 A153779 * A153781 A153782 A153783`
	KEYWORD	`easy,nonn`
	AUTHOR	`Omar E. Pol (info(AT)polprimos.com), Jan 01 2009`

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Last modified February 14 20:38 EST 2012. Contains 205663 sequences.