A089308 Triangle read by rows, in which n-th row contains n numbers starting with n and in increasing order such that the product of the terms + 1 gives the smallest such prime.

1, 2, 3, 3, 4, 5, 4, 5, 6, 10, 5, 6, 7, 8, 9, 6, 7, 8, 9, 10, 11, 7, 8, 9, 10, 11, 12, 14, 8, 9, 10, 11, 12, 14, 15, 16, 9, 10, 11, 12, 13, 14, 15, 16, 21, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23

Offset

1,2

Comments

It is not always the case that the first n-1 terms are n,n+1, n+2, ... 2n-2 etc. and then the last term chosen to yield a prime. The choice of the terms is the one that yields the least prime.

Links

Table of n, a(n) for n=1..78.

Example

1
2 3
3 4 5
4 5 6 10
5 6 7 8 9
...
a(22)..a(28)=7,8,9,10,11,12,14 is the strictly increasing sequence that yields the smallest prime A089307(7)=9313921 of the form 7*n2*n3*..*n7+1, 7<n2<...<n7.

Crossrefs

Cf. A089307.

Sequence in context: A120244 A094727 A341511 * A305579 A321440 A115729

Adjacent sequences: A089305 A089306 A089307 * A089309 A089310 A089311

Keyword

nonn,tabl

Author

Amarnath Murthy, Nov 01 2003

Extensions

More terms from Hugo Pfoertner, Apr 06 2004

Status

approved