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A062302 Number of ways writing n-th 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

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Last modified November 27 15:11 EST 2020. Contains 338683 sequences. (Running on oeis4.)