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A074279 n appears n^2 times. 2
1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

Since the last occurrence of n comes one before the first occurrence of n+1 and the former is at SUM[i=0..n](i^2) = A000330(n), we have a(A000330(n)) = a(n*(n+1)*(2n+1)/6) = n and a(1+A000330(n)) = a(1+(n*(n+1)*(2n+1)/6)) = n+1. The current sequence is, loosely, the inverse function of the square pyramidal sequence. See also: A000330 Square pyramidal numbers: 0^2+1^2+2^2+...+n^2 = n(n+1)(2n+1)/6. A000330 has many alternative formulae, thus yielding many alternative formulae for the current sequence. - Jonathan Vos Post (jvospost3(AT)gmail.com), Mar 18 2006

LINKS

Y.-F. S. Petermann, J.-L. Remy and I. Vardi, Discrete derivatives of sequences, Adv. in Appl. Math. 27 (2001), 562-84.

CROSSREFS

Cf. A000217, A000330, A006331, A050446, A050447, A000537, A006003, A005900.

Sequence in context: A066339 A052375 A171626 * A072750 A186437 A029835

Adjacent sequences:  A074276 A074277 A074278 * A074280 A074281 A074282

KEYWORD

nonn

AUTHOR

Jon Perry (perry(AT)globalnet.co.uk), Sep 21 2002

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Last modified February 17 14:50 EST 2012. Contains 206050 sequences.