A309760 Even numbers k such that k-p is composite where p is the largest prime <= k.

122, 148, 190, 208, 220, 250, 292, 302, 326, 346, 418, 430, 476, 518, 532, 538, 556, 586, 628, 640, 670, 700, 718, 782, 796, 806, 820, 838, 848, 872, 896, 902, 928, 962, 1006, 1030, 1048, 1060, 1078, 1084, 1138, 1144, 1150, 1162, 1180, 1210, 1246, 1258, 1268, 1274

Offset

1,1

Links

Table of n, a(n) for n=1..50.

Mathematica

Select[Range[4, 1274, 2], CompositeQ[# - NextPrime[#, -1]] &] (* Amiram Eldar, Sep 17 2019 *)

Prog

(PARI) is(n) = if(n%2==1 ||n==2, return(0)); my(c = n - precprime(n)); !isprime(c) && c != 1 \\ David A. Corneth, Aug 21 2019

Crossrefs

Cf. A007917, A018252, A049711, A025583.

Sequence in context: A138026 A077030 A280733 * A224606 A224599 A207147

Adjacent sequences: A309757 A309758 A309759 * A309761 A309762 A309763

Keyword

nonn

Author

Aaron Schäfers, Aug 15 2019

Status

approved