A117528 Prime at which the cumulative sum in A117527 is prime.

2, 3, 13, 41, 43, 109, 137, 167, 181, 199, 307, 373, 421, 491, 587, 661, 1009, 1097, 1117, 1373, 1471, 1483, 1601, 1607, 1787, 1913, 2053, 2089, 2203, 2267, 2591, 2819, 2953, 3191, 3361, 3623, 3691, 3779, 3877, 4051

Offset

1,1

Comments

At the twin primes 41 and 43, we obtain consecutive prime integer sums of 641 and 757.

Links

Table of n, a(n) for n=1..40.

Formula

Multiply consecutive primes by e, take integer, sum until a prime sum is reached.

Example

In a(5)=4007, multiplication of the prime 109*e resulted in the int sum 296. When added to previous sums, the total came to 4007, a prime.

Prog

(UBASIC)
10 Ct=1
20 B=nxtprm(B)
22 E=#e
30 C=int(B*E)
40 D=D+C
41 print Ct, B, C, D
50 if D=prmdiv(D) then print D:stop
55 Ct=Ct+1
60 goto 20

Crossrefs

Cf. A117527 A117504.

Sequence in context: A259261 A141511 A235615 * A264042 A122719 A106866

Adjacent sequences: A117525 A117526 A117527 * A117529 A117530 A117531

Keyword

easy,nonn

Author

Enoch Haga, Mar 25 2006

Status

approved