[seqfan] Re: A171228 (?)

Andrew Weimholt andrew.weimholt at gmail.com
Tue Dec 8 13:25:14 CET 2009


On Tue, Dec 8, 2009 at 4:06 AM, zak seidov <zakseidov at yahoo.com> wrote:
> Does anyone understand this?
> I wrote to author but didn't get answer.
>
> %S A171228 0,1,2,9,4,25,6,2401,512,81,10,121,12,28561,2744,225,16,289,18,130321,
> 8000,441,22,148035889,7962624,390625,17576,729,28,841,30,887503681,
> 33554432,1185921,39304,1225,36,1874161,54872,1521,40,1681,42,3418801
> %N A171228 n^nextprime(n).
> %F A171228 a(n)=(n-1)^(smallest prime>(n-1)).
> %Y A171228 Cf. A013632, A013636.
> %K A171228 nonn,new
> %O A171228 1,3
> %A A171228 Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Dec 05 2009
>

Seems to be...
a(n) = (n-1)^(distance from n-1 to next prime after n-1)

0^2, 1^1, 2^1, 3^2, 4^1, 5^2, 6^1, 7^4, 8^3, 9^2, 10^1, 11^2, 12^1, 13^4, ...

Offset should be 0,
then the title could be...

n^(p-n) where p is the smallest prime greater than n.

Andrew




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