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A039596
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Numbers that are simultaneously triangular and square pyramidal.
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3
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OFFSET
| 1,2
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COMMENTS
| Equivalent to 1^2+2^2+3^2+...+r^2 = 1+2+3+...+s = n for some r and s.
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REFERENCES
| D. Wells, Curious and interesting numbers, Penguin Books, p. 108
Joe Roberts, Lure of the Integers, page 245 (entry for 645).
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EXAMPLE
| 1^2+2^2+3^2+4^2+5^2 = 1+2+3+...+10 = 55, so 55 is in the sequence.
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CROSSREFS
| Cf. A000330.
Sequence in context: A063873 A063131 A128880 * A013543 A115377 A146145
Adjacent sequences: A039593 A039594 A039595 * A039597 A039598 A039599
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KEYWORD
| fini,nonn,full
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AUTHOR
| Felice Russo (frusso(AT)micron.com)
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EXTENSIONS
| Additional comments from Jud McCranie (JudMcCranie(AT)ugaalum.uga.edu), Mar 19 2000
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