id:A076767 - OEIS Search Results

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Triangular numbers with square pyramidal indices.

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0, 1, 15, 105, 465, 1540, 4186, 9870, 20910, 40755, 74305, 128271, 211575, 335790, 515620, 769420, 1119756, 1594005, 2224995, 3051685, 4119885, 5483016, 7202910, 9350650, 12007450, 15265575, 19229301, 24015915, 29756755, 36598290 (list; graph; listen)

	OFFSET	`0,3`
	FORMULA	`let SP(m) be the m-th square pyramidal number m(m+1)(2m+1)/6 and T(k) be the k-th Triangular number k(k+1)/2 then a(n)=T(SP(n))`
	EXAMPLE	`SP(3)=14 -> a(3)=T(SP(3))=T(14)=105; SP(4)=30 -> a(4)=T(SP(4))=T(30)=465 etc`
	CROSSREFS	`Cf. A077538.` `Sequence in context: A090454 A047640 A010931 this_sequence A022610 A006857 A000478` `Adjacent sequences: A076764 A076765 A076766 this_sequence A076768 A076769 A076770`
	KEYWORD	`easy,nonn`
	AUTHOR	`Bruce Corrigan (scentman(AT)myfamily.com), Nov 14 2002`

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Last modified July 26 13:41 EDT 2008. Contains 142293 sequences.

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