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Search: id:A061078
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| A061078 |
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Sum of the products of the digits of the first n even numbers. |
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+0
2
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| 2, 6, 12, 20, 20, 22, 26, 32, 40, 40, 44, 52, 64, 80, 80, 86, 98, 116, 140, 140, 148, 164, 188, 220, 220, 230, 250, 280, 320, 320, 332, 356, 392, 440, 440, 454, 482, 524, 580, 580, 596, 628, 676, 740, 740, 758, 794, 848, 920, 920, 920, 920, 920, 920, 920, 922
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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For n = (10^r)/2, a(n) is the sum of the r terms of the geometric progression with first term 20 and common ratio 45.
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REFERENCES
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A. Murthy, Smarandache friendly numbers and a few more sequences, Smarandache Notions Journal, Vol. 12, No. 1-2-3, Spring 2001.
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LINKS
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Matthew M. Conroy, Home page (listed instead of email address)
M. L. Perez et al., eds., Smarandache Notions Journal
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EXAMPLE
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a(5) = 2+4+6+8+1x0 = 20; (a(18)=116 not 114)
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CROSSREFS
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Cf. A061076, A061077.
Sequence in context: A130492 A152222 A139082 this_sequence A067114 A102711 A141406
Adjacent sequences: A061075 A061076 A061077 this_sequence A061079 A061080 A061081
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KEYWORD
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nonn,base
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Apr 14 2001
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EXTENSIONS
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Corrected and extended by Matthew M. Conroy, Apr 17 2001
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