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A078725 Prime(n*(n+1)/2+4). +0
1
7, 11, 17, 29, 43, 67, 97, 131, 173, 227, 277, 349, 421, 499, 599, 683, 809, 919, 1039, 1181, 1307, 1483, 1621, 1811, 2003, 2207, 2389, 2633, 2819, 3067, 3329, 3571, 3833, 4099, 4397, 4691, 5003, 5347, 5657, 6007, 6329, 6703, 7057, 7499, 7873, 8287, 8707, 9133 (list; graph; listen)
OFFSET

0,1

FORMULA

More generally one may consider the sequence S(n, m) = prime(n*(n+1)/2+m+1), for m=1, 2, 3...

PROGRAM

(PARI) triprimes(n, m) = { sr = 0; for(j=m, n, x = j*(j+1)/2+m+1; z = prime(x); sr+=1.0/z; print1(z" "); ); print(); print(sr); }

CROSSREFS

Apart from initial terms, primes in fourth diagonal of triangle in A078721.

Adjacent sequences: A078722 A078723 A078724 this_sequence A078726 A078727 A078728

Sequence in context: A021013 A062574 A063912 this_sequence A019418 A068674 A107642

KEYWORD

easy,nonn

AUTHOR

Cino Hilliard (hillcino368(AT)gmail.com), Dec 20 2002

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Last modified October 13 20:18 EDT 2008. Contains 145016 sequences.


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