A176915 Average of n-th twin prime pair minus total number of prime factors of average of n-th twin prime pair.

2, 4, 9, 15, 27, 39, 56, 67, 99, 103, 135, 146, 175, 185, 194, 224, 234, 265, 279, 307, 344, 415, 425, 458, 518, 566, 594, 615, 639, 655, 804, 819, 823, 854, 877, 1015, 1027, 1045, 1058, 1087, 1143, 1226, 1274, 1286, 1298, 1314, 1423, 1447, 1478, 1482, 1603

Offset: 1

Author

Juri-Stepan Gerasimov, Apr 28 2010

Keywords

• nonn
• easy
• changed

Comments

Prime factors are counted with multiplicity. - Harvey P. Dale, Aug 19 2011

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf, A014574, A069345, A078571.

Programs

Maple

TP:= select(t -> isprime(t) and isprime(t+2), [3, seq(i,i=5..2000,6)]):
map(t -> t+1 - numtheory:-bigomega(t+1), P1); # Robert Israel, Dec 31 2024

Mathematica

f[n_]:=Module[{mn=Mean[n]},mn-PrimeOmega[mn]]; f/@Select[Partition[ Prime[ Range[300]],2,1],Last[#]-First[#]==2&] (* Harvey P. Dale, Aug 19 2011 *)

Formula

a(n) = A014574(n)-A078571(n).

a(n) = A069345(A014574(n)). - Jason Yuen, Sep 01 2025

Extensions

Formula index, a(8), a(15) and a(23) corrected by R. J. Mathar, May 01 2010