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A138125
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Final digit of n-th even superperfect number A061652(n).
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6
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2, 4, 6, 4, 6, 6, 4, 4, 6, 6, 4, 4, 6, 4, 4, 4, 6, 6, 6, 4, 6, 6, 6, 6, 6, 6, 6, 4, 4, 6, 4, 4, 6, 4, 6, 6, 6, 6, 6
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Also, final digit of n-th superperfect number A019279(n), if there are no odd superperfect numbers.
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LINKS
| Landon Curt Noll, Mersenne Prime Digits and Names.
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FORMULA
| a(1)=2. For n>1, if final digit of n-th Mersenne prime A000668(n) is equal to 1 then a(n)=6, otherwise a(n)=4.
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EXAMPLE
| a(5)=6 because the 5th even superperfect number A061652(5) is 4096 and the final digit of 4096 is 6.
a(34)=4 because the final digit of 34th Mersenne prime is 7. a(39)=6 because the final digit of 39th Mersenne prime is 1.
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............... SHORT TABLE OF FINAL DIGITS .................
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Final digit of ..... Final digit of Even ..... Final digit of
Mersenne prime ..... Superperfect number ..... Perfect number
A000668 ............ A061652 ................. A000396........
(3) ................ (2) ..................... (6) ........... (For n=1, only)
(7) ................ (4) ..................... (8) ...........
(1) ................ (6) ..................... (6) ...........
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CROSSREFS
| Cf. A000030, A000396, A000668, A077648, A019279, A061652, A135613, A135617, A138125.
Sequence in context: A163234 A072984 A018841 * A098793 A083220 A085896
Adjacent sequences: A138122 A138123 A138124 * A138126 A138127 A138128
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KEYWORD
| base,nonn
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AUTHOR
| Omar E. Pol (info(AT)polprimos.com), Apr 01 2008, corrected Apr 03 2008
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