

A062302


Number of ways writing nth prime as a sum of a prime and a nonprime.


2



0, 1, 0, 1, 4, 3, 6, 5, 8, 9, 8, 11, 12, 11, 14, 15, 16, 15, 18, 19, 18, 21, 22, 23, 24, 25, 24, 27, 26, 29, 30, 31, 32, 31, 34, 33, 36, 37, 38, 39, 40, 39, 42, 41, 44, 43, 46, 47, 48, 47, 50, 51, 50, 53, 54, 55, 56, 55, 58, 59, 58, 61, 62, 63, 62, 65, 66, 67, 68, 67, 70, 71, 72
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,5


LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000


FORMULA

a(n) = A062602(A000040(n)) = number of [nonprime+prime] partitions of prime(n)


MATHEMATICA

Table[c = 0; Do[i = Prime[k]; If[i + j == Prime[n] && ! PrimeQ[j], c = c + 1], {k, n  1}, {j, Prime[n]  1}]; c, {n, 73}] (* Jayanta Basu, Apr 22 2013 *)
nn = 100; mx = Prime[nn]; ps = Prime[Range[nn]]; notPs = Complement[Range[mx], ps]; t2 = Table[0, {Range[mx]}]; Do[s = i + j; If[s <= mx, t2[[s]]++], {i, ps}, {j, notPs}]; t2[[ps]] (* T. D. Noe, Apr 23 2013 *)


CROSSREFS

Cf. A061358, A062602, A000040, A014092, A025584.
Sequence in context: A219176 A251739 A224715 * A261723 A021233 A290612
Adjacent sequences: A062299 A062300 A062301 * A062303 A062304 A062305


KEYWORD

nonn


AUTHOR

Labos Elemer, Jul 05 2001


STATUS

approved



