

A039915


Smallest k such that k(p1)1 is positive and divisible by p where p = nth prime.


5



3, 2, 4, 6, 10, 12, 16, 18, 22, 28, 30, 36, 40, 42, 46, 52, 58, 60, 66, 70, 72, 78, 82, 88, 96, 100, 102, 106, 108, 112, 126, 130, 136, 138, 148, 150, 156, 162, 166, 172, 178, 180, 190, 192, 196, 198, 210, 222, 226, 228, 232, 238, 240, 250, 256, 262, 268, 270
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OFFSET

1,1


COMMENTS

Also smallest positive k such that the kth triangular number is divisible by the nth prime.  Reinhard Zumkeller, Apr 19 2002


LINKS

T. D. Noe, Table of n, a(n) for n=1..1000


FORMULA

a(n) = p+(1)^p.  JuriStepan Gerasimov, May 26 2009


EXAMPLE

a(1)=3 because 3(21)1=2 is divisible by 2.


MATHEMATICA

kp[n_]:=Module[{p=Prime[n], k=1}, While[!Divisible[(k(k+1))/2, p], k++]; k]; Array[kp, 60] (* Harvey P. Dale, Jun 12 2012 *)
a[n_] := Prime[n]1; a[1]=3; Table[a[n], {n, 1, 58}] (* JeanFrançois Alcover, Dec 26 2012, after JuriStepan Gerasimov *)


CROSSREFS

Cf. A000217, A039678.
Essentially the same as A006093.
Sequence in context: A240493 A095258 A114745 * A085346 A121861 A317736
Adjacent sequences: A039912 A039913 A039914 * A039916 A039917 A039918


KEYWORD

nonn


AUTHOR

Felice Russo


EXTENSIONS

Edited and extended by Ray Chandler, Jun 06 2008


STATUS

approved



