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Search: id:A068401
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| A068401 |
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Numbers n such that sigma(n)=phi(n+1)+phi(n-1). |
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+0
1
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| 2, 38, 62, 346, 1298, 7898, 22682, 24382, 93022, 108194, 143362, 171982, 192718, 264766, 587638, 986642, 1236898, 1441042, 1604422, 2228582, 4146434, 5070314, 5631718, 6687046, 10223918, 10695182, 12465158
(list; graph; listen)
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OFFSET
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1,1
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PROGRAM
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(PARI) for(n=2, 12500000, if(sigma(n)==eulerphi(n+1)+eulerphi(n-1), print1(n, ", ")))
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CROSSREFS
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Sequence in context: A110762 A049487 A050899 this_sequence A050248 A075459 A105645
Adjacent sequences: A068398 A068399 A068400 this_sequence A068402 A068403 A068404
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KEYWORD
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easy,nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Mar 02 2002
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EXTENSIONS
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More terms from Rick L. Shepherd (rshepherd2(AT)hotmail.com), Jul 04 2002
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