login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A270828 a(n) = (Sum_{k=1..2n-1} prime(k)) mod prime(n). 1
0, 1, 3, 2, 1, 4, 0, 5, 3, 17, 30, 23, 35, 17, 23, 24, 41, 19, 38, 3, 54, 4, 44, 77, 38, 98, 62, 25, 3, 73, 108, 67, 27, 124, 108, 66, 34, 4, 130, 102, 80, 40, 32, 169, 132, 78, 79, 128, 75, 5, 215, 227, 189, 243, 255, 259, 261, 193, 197, 162, 98, 148, 9, 281, 213, 194, 87, 109, 261, 171 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(n) = 0 for n = 1, 7, 100. Are there any other values?

No other zero up to n=200000. - Michel Marcus, Jan 31 2019

LINKS

Michel Marcus, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A007504(2*n-1) mod A000040(n).

EXAMPLE

a(2) = 1 because (2 + 3 + 5) mod 3 = 1.

a(7) = 0 because (2 + 3 + 5 + 7 + 11 + 13 + 17 + 19 + 23 + 29 + 31 + 37 + 41) mod 17 = 238 mod 17 = 0.

MATHEMATICA

Table[Mod[Sum[Prime@ k, {k, 2 n - 1}], Prime@ n], {n, 70}] (* Michael De Vlieger, Mar 24 2016 *)

PROG

(PARI) for(n=1, 1e2, print1(sum(k=1, 2*n-1, prime(k)) % prime(n), ", "));

(PARI) lista(nn) = {my(s=0, p=1); for (n=1, nn, p = nextprime(p+1); s += p; print1(s % prime(n), ", "); p = nextprime(p+1); s += p; ); } \\ Michel Marcus, Jan 31 2019

CROSSREFS

Cf. A000040, A007504, A109723.

Sequence in context: A025261 A111572 A046900 * A325315 A230845 A194528

Adjacent sequences:  A270825 A270826 A270827 * A270829 A270830 A270831

KEYWORD

nonn

AUTHOR

Altug Alkan, Mar 23 2016

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 16 22:05 EST 2019. Contains 329208 sequences. (Running on oeis4.)