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A131280 Sums of exactly 4 positive octahedral numbers A005900. +0
11
4, 9, 14, 19, 22, 24, 27, 32, 37, 40, 45, 47, 50, 52, 57, 58, 62, 63, 65, 70, 75, 76, 83, 88, 90, 93, 95, 98, 100, 101, 103, 106, 108, 111, 113, 116, 124, 126, 129, 131, 133, 136, 138, 141, 142, 149, 151, 154, 159, 164, 167, 172, 174, 176, 177, 179, 182, 185, 190 (list; graph; listen)
OFFSET

1,1

COMMENT

Pollock (1850) conjectured that every number is the sum of at most 7 octahedral numbers. Which octahedral numbers are themselves the sum of exactly 4 positive octahedral numbers? To begin with, Oc(3) = Oc(2) + Oc(2) + Oc(2) + Oc(1) = 6 + 6 + 6 + 1 = 19.

REFERENCES

Dickson, L. E. History of the Theory of Numbers, Vol. 2: Diophantine Analysis. New York: Dover, 2005, cites the Pollock reference.

Pollock, F. "On the Extension of the Principle of Fermat's Theorem of the Polygonal Numbers to the Higher Orders of Series Whose Ultimate Differences Are Constant. With a New Theorem Proposed, Applicable to All the Orders." Abs. Papers Commun. Roy. Soc. London 5, 922-924, 1843-1850.

CROSSREFS

Cf. A005900, A053676-A053678, A133330.

Sequence in context: A070799 A031474 A045203 this_sequence A120433 A016897 A045293

Adjacent sequences: A131277 A131278 A131279 this_sequence A131281 A131282 A131283

KEYWORD

easy,nonn

AUTHOR

Jonathan Vos Post (jvospost3(AT)gmail.com), Oct 21 2007

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Last modified December 2 15:58 EST 2008. Contains 150992 sequences.


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