A079950 - OEIS

A079950

Triangle of n-th prime modulo twice primes less n-th prime.

2, 3, 3, 1, 5, 5, 3, 1, 7, 7, 3, 5, 1, 11, 11, 1, 1, 3, 13, 13, 13, 1, 5, 7, 3, 17, 17, 17, 3, 1, 9, 5, 19, 19, 19, 19, 3, 5, 3, 9, 1, 23, 23, 23, 23, 1, 5, 9, 1, 7, 3, 29, 29, 29, 29, 3, 1, 1, 3, 9, 5, 31, 31, 31, 31, 31, 1, 1, 7, 9, 15, 11, 3, 37, 37, 37, 37, 37, 1, 5, 1, 13, 19, 15, 7, 3, 41

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

The right border of the triangle are the primes: T(n,n)=A000040(n); T(n,1)=A039702(n), T(n,2)=A039704(n) for n>1, T(n,3)=A007652(n) for n>2, T(n,4)=A039712(n) for n>3;

LINKS

Table of n, a(n) for n=1..87.

FORMULA

T(n, k) = prime(n) mod 2*prime(k), 1<=k<=n.

EXAMPLE

Triangle begins:

3, 3;

1, 5, 5;

3, 1, 7, 7;

3, 5, 1, 11, 11;

1, 1, 3, 13, 13, 13;

1, 5, 7, 3, 17, 17, 17;

...

MAPLE

A079950 := proc(n, k)

modp(ithprime(n), 2*ithprime(k)) ;

end proc:

seq(seq(A079950(n, k), k=1..n), n=1..12) ; # _R. J. Mathar_, Sep 28 2017

PROG

(PARI) T(n, k) = prime(n) % (2*prime(k));

tabl(nn) = for (n=1, nn, for (k=1, n, print1(T(n, k), ", ")); print); \\ _Michel Marcus_, Sep 21 2017

CROSSREFS

Cf. A001747, A079951, A079952, A079953.

Sequence in context: A334362 A035516 A120428 * A174953 A298599 A138677

Adjacent sequences: A079947 A079948 A079949 * A079951 A079952 A079953

KEYWORD

nonn,tabl

AUTHOR

_Reinhard Zumkeller_, Jan 19 2003

STATUS

approved