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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A174953 Triangle read by rows: R(n,k) = prime(n) mod semiprime(k), 1<=k<=n. 0
2, 3, 3, 1, 5, 5, 3, 1, 7, 7, 3, 5, 2, 1, 11, 1, 1, 4, 3, 13, 13, 1, 5, 8, 7, 3, 2, 17, 3, 1, 1, 9, 5, 4, 19, 19, 3, 5, 5, 3, 9, 8, 2, 1, 23, 1, 5, 2, 9, 1, 14, 8, 7, 4, 3, 3, 1, 4, 1, 3, 1, 10, 9, 6, 5, 31, 1, 1, 1, 7, 9, 7, 16, 15, 12, 11, 4, 3, 1, 5, 5, 1, 13, 11, 20, 19, 16, 15, 8, 7, 6, 3, 1, 7, 3, 1, 13, 1, 21, 18, 17, 10, 9, 8, 5 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..105.

EXAMPLE

The triangle starts as

  2;

  3,  3;

  1,  5,  5;

  3,  1,  7,  7;

  3,  5,  2,  1, 11;

  1,  1,  4,  3, 13, 13;

  1,  5,  8,  7,  3,  2, 17;

  3,  1,  1,  9,  5,  4, 19, 19;

  3,  5,  5,  3,  9,  8,  2,  1, 23;

  1,  5,  2,  9,  1, 14,  8,  7,  4,  3;

PROG

(MAGMA) IsSemiprime:=func< n | &+[ k[2]: k in Factorization(n) ] eq 2 >; splt:=38; T:=[ n: n in [2..splt] | IsSemiprime(n) ]; &cat[ [ NthPrime(n) mod T[k]: k in [1..n] ]: n in [1..#T] ]; // Klaus Brockhaus, Dec 02 2010

CROSSREFS

Cf A001358.

Sequence in context: A035516 A120428 A079950 * A298599 A138677 A193885

Adjacent sequences:  A174950 A174951 A174952 * A174954 A174955 A174956

KEYWORD

nonn,tabl,easy

AUTHOR

Juri-Stepan Gerasimov, Dec 02 2010

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified February 23 11:27 EST 2018. Contains 299571 sequences. (Running on oeis4.)