A268146 Twin prime pairs concatenated to their average in decimal representation (the greater twin prepended, the lesser appended).

543, 765, 131211, 191817, 313029, 434241, 616059, 737271, 103102101, 109108107, 139138137, 151150149, 181180179, 193192191, 199198197, 229228227, 241240239, 271270269, 283282281, 313312311, 349348347, 421420419, 433432431, 463462461, 523522521, 571570569, 601600599

Offset

1,1

Comments

The greater prime of a twin prime pair is prepended and the lesser one is appended to their average (nonprime, interprime).

a(n) mod 3 = 0, (See A095958).

Links

Table of n, a(n) for n=1..27.

Example

a(1)=543: the greater prime {5} of the first twin prime pair {3, 5} is prepended and the lesser prime {3} is appended to their average {4}.

Mathematica

UpToN[k_]:=FromDigits//@ StringJoin//@ ToString/@ {#+1, #, #-1} &/@ Select[ Table[ Prime[n]+1, {n, 2, PrimePi[k]}], PrimeQ[#+1] &]; UpToN[10000]

Crossrefs

Cf. A001097, A014574, A095958, A111875, A268145.

Sequence in context: A232707 A334771 A163764 * A074888 A250854 A250685

Adjacent sequences: A268143 A268144 A268145 * A268147 A268148 A268149

Keyword

nonn,base,easy

Author

Mikk Heidemaa, Jan 27 2016

Status

approved