A194265 -id:A194265 - cp's OEIS frontend

A195266 Trajectory of 105 under iteration of the map x -> A080670(x).

105, 357, 3717, 32759, 174147, 358049, 379677, 3196661, 13245897, 373120347, 31961239449, 364811643843, 3474632755849, 7148938489519, 19530970872089, 731453184134581, 1069684240583849, 11451757737372871, 18163269379764491, 99042547183388553, 344278174560973471, 71388716692555572127, 148872380947952962303, 1453102458624189919451, 11245912921175349453489

Offset: 1

N. J. A. Sloane, Sep 14 2011, based on a posting to the Sequence Fans Mailing List by Alonso del Arte

Sean A. Irvine, Table of n, a(n) for n = 1..108 (1..40 from _Alonso del Arte_, 41..65 from _D. S. McNeil_, 66..108 from _Sean A. Irvine_)

Cf. A080670, A195264, A194265.

read("transforms");
# insert A080670 here
A195266 := proc(n)
        option remember;
        if n = 1 then
                105;
        else
                A080670(procname(n-1)) ;
        end if;
end proc: # R. J. Mathar, Oct 02 2011

A194266 Smallest sum of two distinct primes of the form n*k+1.

Original entry on oeis.org

5, 8, 20, 18, 42, 20, 72, 58, 56, 42, 90, 50, 132, 72, 92, 114, 240, 56, 420, 102, 170, 90, 186, 170, 252, 132, 272, 142, 292, 92, 684, 290, 266, 240, 282, 110, 372, 420, 236, 282, 822, 170, 604, 442, 452, 186, 942, 290, 688, 252, 410, 210, 850, 272, 992

Offset: 1

Omar E. Pol, Sep 03 2011

nonn

			a(1) = 2+3 = 5
a(2) = 3+5 = 8
a(3) = 7+13 = 20
a(4) = 5+13 = 18
a(5) = 11+31 = 42
a(6) = 7+13 = 20

Cf. A077318, A132810, A194265, A194267.

Table[ps = Select[Table[n*k + 1, {k, 100}], PrimeQ, 2]; If[Length[ps] == 2, Total[ps], 0], {n, 100}] (* T. D. Noe, Oct 21 2011 *)

cp's OEIS Frontend

A195266 Trajectory of 105 under iteration of the map x -> A080670(x).

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