A071196 The sum of the sequence starting with prime(n) and having prime sum defined in A071194, or -1 if no such sequence exists.

5, 127, 23, 31, 41, 101, 59, 71, 83, 97, 109, 479, 131, 263, 431, 173, 331, 199, 211, 223, 421, 251, 269, 719, 757, 311, 827, 587, 349, 647, 683, 1367, 733, 439, 457, 811, 487, 503, 2141, 1747, 941, 5009, 991, 1951, 607, 2053, 661, 1151, 21139, 701, 1753

Offset

1,1

Links

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Rémy Sigrist, Colored logarithmic scatterplot of the first 10000 terms (where the color is function of A071194(n))

Example

n=25: prime(25)=97, sum=97+101+103+107+109+113+127=757=a(25), prime; shorter (length>1) partial sums are composite: {97,198,301,408,517,630,757}.

Mathematica

Table[sm = Prime[k] + Prime[k + 1]; g = 1; While[ ! PrimeQ[sm], g++; sm = sm + Prime[k + g]]; sm, {k, 1, 51}] (* Lei Zhou, Dec 02 2005 *)

Prog

(PARI) { forprime (p=2, prime(51), s=p; forprime (q=p+1, oo, if (isprime(s+=q), print1 (s", "); break))) } \\ Rémy Sigrist, Nov 17 2020

Crossrefs

Cf. A000040, A071194, A071195, A071197, A071198.

Sequence in context: A156956 A015476 A059486 * A357133 A115233 A157438

Adjacent sequences: A071193 A071194 A071195 * A071197 A071198 A071199

Keyword

nonn,look

Author

Labos Elemer, May 16 2002

Extensions

Edited and escape clause added by N. J. A. Sloane, Nov 17 2020~

Status

approved