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A055514 Composite numbers that are the sum of a string of consecutive prime numbers and are divisible by the first and last primes. 6
10, 39, 155, 371, 10225245560, 2935561623745, 454539357304421, 7228559051256366318, 1390718713078158117206 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Composite n such that n = p_1 + p_2 + ... + p_k where the p_i are consecutive primes and n is divisible by p_1 and p_k.

No more terms below 10^22. - Michael Beight, Jul 22 2012

REFERENCES

Problem proposed by Carlos Rivera, who found first 4 terms.

LINKS

Table of n, a(n) for n=1..9.

C. Rivera, Puzzle

EXAMPLE

503 + 509 + 521+ ... + 508213 = 10225245560, which is divisible by 503 and 508213. - Manuel Valdivia, Nov 17 2011

From Michael Beight, Jul 22 2012: (Start)

a(8) = 7228559051256366318 = 73 + ... + 18281691653;

a(9) = 1390718713078158117206 = 370794889 + ... + 267902967061. (End)

CROSSREFS

Cf. A055233.

Sequence in context: A267748 A229325 A074225 * A055233 A267626 A189947

Adjacent sequences:  A055511 A055512 A055513 * A055515 A055516 A055517

KEYWORD

nice,nonn

AUTHOR

Jud McCranie, Jul 03 2000

EXTENSIONS

a(7) from Donovan Johnson, Jun 19 2008

a(8) and a(9) from Michael Beight, Jul 22 2012

STATUS

approved

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Last modified June 14 13:23 EDT 2021. Contains 345025 sequences. (Running on oeis4.)