A098350 - OEIS

A098350

Multiplication table of the primes read by antidiagonals.

4, 6, 6, 10, 9, 10, 14, 15, 15, 14, 22, 21, 25, 21, 22, 26, 33, 35, 35, 33, 26, 34, 39, 55, 49, 55, 39, 34, 38, 51, 65, 77, 77, 65, 51, 38, 46, 57, 85, 91, 121, 91, 85, 57, 46, 58, 69, 95, 119, 143, 143, 119, 95, 69, 58, 62, 87, 115, 133, 187, 169, 187, 133, 115, 87, 62

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

OFFSET

1,1

COMMENTS

Contains only semiprimes (A001358).

sum{n>=1, k>=1} 1/T(n,k)^s = P(s)^2, where P is the Prime Zeta Function. - Enrique Pérez Herrero, Jun 24 2012

LINKS

Table of n, a(n) for n=1..66.

FORMULA

T(n,k) = A003991(prime(n),prime(k)).

T(n,k) = T(k,n) = A087112(n,k).

EXAMPLE

4, 6, 10, 14, 22, 26, 34, 38, 46, 58,...

6, 9, 15, 21, 33, 39, 51, 57, 69, 87,...

10, 15, 25, 35, 55, 65, 85, 95,115,145,...

14, 21, 35, 49, 77, 91,119,133,161,203,...

22, 33, 55, 77,121,143,187,209,253,319,...

26, 39, 65, 91,143,169,221,247,299,377,...

34, 51, 85,119,187,221,289,323,391,493,...

CROSSREFS

Cf. A098351, A006881.

Sequence in context: A215454 A155750 A159475 * A276269 A163173 A058640

Adjacent sequences: A098347 A098348 A098349 * A098351 A098352 A098353

KEYWORD

nonn,tabl

AUTHOR

Douglas Stones (dssto1(AT)student.monash.edu.au), Sep 04 2004

STATUS

approved