|
Search: id:A123541
|
|
|
| A123541 |
|
a(0) = 2; for n > 0, a(n) = number of earlier terms which when added to n give a prime. |
|
+0
5
|
|
| 2, 1, 1, 1, 3, 1, 4, 1, 1, 2, 7, 2, 7, 1, 1, 4, 11, 3, 9, 2, 4, 4, 11, 0, 2, 4, 4, 11, 11, 6, 14, 2, 5, 7, 6, 8, 16, 10, 4, 15, 13, 9, 13, 10, 5, 9, 14, 5, 9, 9, 11, 10, 17, 6, 9, 11, 13, 19, 20, 11, 22, 8, 17, 14, 13, 14, 20, 13, 13, 22, 23, 9, 20, 8, 12, 16, 11, 13, 21, 13, 13, 16, 14, 12, 16, 15
(list; graph; listen)
|
|
|
OFFSET
|
0,1
|
|
|
LINKS
|
T. D. Noe, Table of n, a(n) for n=0..2000
|
|
FORMULA
|
a(n) = A114897(n+1) for n>2. - T. D. Noe (noe(AT)sspectra.com), Apr 30 2007
|
|
MAPLE
|
M:=100; a:=array(0..M); a[0]:=2; for n from 1 to M do t1:=0; for i from 0 to n-1 do if isprime(n+a[i]) then t1:=t1+1; fi; od: a[n]:=t1; od: [seq(a[n], n=0..M)];
|
|
MATHEMATICA
|
t={2}; Do[AppendTo[t, Length[Select[t+n, PrimeQ]]], {n, 2000}]; t - T. D. Noe (noe(AT)sspectra.com), Apr 30 2007
|
|
CROSSREFS
|
Cf. A114899
Sequence in context: A091981 A060247 A060246 this_sequence A090379 A077254 A074761
Adjacent sequences: A123538 A123539 A123540 this_sequence A123542 A123543 A123544
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
N. J. A. Sloane (njas(AT)research.att.com), based on email from Zak Seidov, Oct 16 2006
|
|
|
Search completed in 0.002 seconds
|
