A109068 - OEIS

A109068

Products of two successive primes that can be partitioned in sum of three distinct primes which contain the prime divisors.

15, 35, 77, 221, 899, 1517, 2021, 5183, 8633, 11663, 23707, 27221, 36863, 41989, 47053, 57599, 60491, 77837, 111547, 164009, 233273, 324899, 372091, 416021, 471953, 522713, 568507, 608351, 665831, 680621

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OFFSET

1,1

COMMENTS

Largest prime of sum of three primes are primes of the form p*q - p - q, where p and q are two successive primes (A096345).

LINKS

Table of n, a(n) for n=1..30.

FORMULA

a(n) = A096345(n) - A001043(n).

EXAMPLE

a(1) = 15 because 15 = 3+5+7 with 3*5 =15;

a(2) = 35 because 35 = 5+7+23 with 5*7=35;

a(3) = 77 because 77 = 7+11+59 with 7*11=77;

a(4) = 221 because 221= 13+17+191 with 13*17=221

PROG

(PARI) lista(nn) = {for (n=1, nn, p = prime(n); q = prime(n+1); prd = p*q; if (isprime(prd - p - q), print1(prd, ", ")); ); } \\ Michel Marcus, Jun 03 2013

CROSSREFS

Cf. A096345.

Sequence in context: A242235 A082663 A368231 * A334309 A238232 A061367

Adjacent sequences: A109065 A109066 A109067 * A109069 A109070 A109071

KEYWORD

nonn

AUTHOR

Giovanni Teofilatto, Aug 17 2005

EXTENSIONS

More terms from Michel Marcus, Jun 03 2013

STATUS

approved