The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A196152

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A196152

a(n) = Sum_{j=1..n} c(j)^c(n+1-j) where c(k) is the k-th composite number.
(history; published version)

#30 by Alois P. Heinz at Tue Aug 24 06:28:38 EDT 2021

STATUS

reviewed

approved

#29 by Hugo Pfoertner at Mon Aug 23 14:32:32 EDT 2021

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proposed

reviewed

#28 by Jon E. Schoenfield at Sat Aug 21 20:25:00 EDT 2021

STATUS

editing

proposed

#27 by Jon E. Schoenfield at Sat Aug 21 20:24:41 EDT 2021

NAME

The sum over i from 1 to n of the i-th composite number to the power of the (n+1-i)-th composite number.

a(n) = Sum_{j=1..n} c(j)^c(n+1-j) where c(k) is the k-th composite number.

COMMENTS

For n smaller that than 100, a(n) can be approximated by exp(0.0075n0075*n^2 + 3.0857n 0857*n - 0.166).

FORMULA

a(n) = Sum_{ij=1->..n} A002808(ij)^A002808(n+1-ij).

EXAMPLE

For n = 4, a(4) = 4^9 + 6^8 + 8^6 + 9^4 = 2210465.

STATUS

approved

editing

Discussion

Sat Aug 21

20:25

Jon E. Schoenfield: I tried to make the Name easier to read.  Is this better?  Worse?  Indifferent?

#26 by Joerg Arndt at Wed Apr 01 12:11:55 EDT 2020

STATUS

reviewed

approved

#25 by Hugo Pfoertner at Wed Apr 01 09:55:19 EDT 2020

STATUS

proposed

reviewed

#24 by Michel Marcus at Wed Apr 01 09:50:42 EDT 2020

STATUS

editing

proposed

#23 by Michel Marcus at Wed Apr 01 09:50:40 EDT 2020

EXAMPLE

For n = 4, a(n4) = 4^9+6^8+8^6+9^4 = 2210465.

STATUS

approved

editing

#22 by Michel Marcus at Wed Aug 06 17:02:54 EDT 2014

STATUS

reviewed

approved

#21 by Bruno Berselli at Wed Aug 06 16:46:49 EDT 2014

STATUS

proposed

reviewed