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A095237
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a(1)=1; then for n even, a(n)=(sum of previous terms times n) plus 1, for n odd, a(n)=(sum of previous terms times n) minus 1.
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1, 3, 11, 61, 379, 2731, 22301, 203897, 2064455, 22938391, 277554529, 3633441109, 51170962283, 771500662115, 12399117783989, 211611610180081, 3822234708877711, 72847296804492847, 1460993008134550985
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Conjecture: There are infinitely many primes in this sequence.
The sequence would have been a little nicer if the even terms had a minus one and the odd a plus one, so the first term would not have to be an exception.
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FORMULA
| a(n) = (n+1)!-floor(((n+1)!+1)/e) - n! + floor((n!+1)/e),n>1 [From Gary Detlefs (gdetlefs(AT)aol.com), Nov 07 2010]
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PROG
| (PARI) a=vector(100) s=1 for(i=2, 100, if(Mod(i, 2)==0, a[i]=s*i+1, a[i]=s*i-1); s+=a[i])
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CROSSREFS
| Cf. A095236.
Sequence in context: A076475 A125556 A127516 * A185385 A024528 A004108
Adjacent sequences: A095234 A095235 A095236 * A095238 A095239 A095240
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KEYWORD
| nonn
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AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jun 13 2004
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EXTENSIONS
| Edited by Johan Claes (Johan.Claes(AT)luc.ac.be), Jun 16 2004
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