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A051902

Minimal primorial safe primes: p and primorial*p + 1 are both primes.

5, 13, 61, 421, 4621, 150151, 8678671, 106696591, 2454021571, 71166625531, 401120980261, 170676977100631, 2129751844690471, 562558737261811291, 11682905869181336791, 97767475431570134191, 9613801750771063195351

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OFFSET

1,1

COMMENTS

In A051888, 13 of the first 25 values are distinct, while here all corresponding min-primorial-safe-primes are different: {2,5,17,11,23,43,19,3,7,61,53,41,47}.

LINKS

Table of n, a(n) for n=1..17.

FORMULA

a(n) = 1 + A002110(n)*A051887(n).

EXAMPLE

The first five terms of A051887 are 2, so the first 5 terms have the form 1 + 2*A002110(n): 5, 13, 61, 421, 4621, which are smallest terms in A005385, A051644, A051646, A051648, A051649. The 6th term here is A051651(1) = A051887(6)*A002110(6) + 1 = 5*30030 + 1.

CROSSREFS

Cf. A005385, A002110, A051644, A051646, A051648, A051649.

Sequence in context: A149568 A201805 A144725 * A269514 A149569 A149570

Adjacent sequences: A051899 A051900 A051901 * A051903 A051904 A051905

KEYWORD

nonn

AUTHOR

Labos Elemer, Dec 16 1999

STATUS

approved