A087200 - OEIS

A087200

a(n) is the smallest m such that m > A005235(n) and A002110(n)+m is prime.

5, 7, 11, 17, 29, 29, 41, 37, 47, 89, 83, 101, 107, 67, 109, 73, 89, 167, 139, 229, 163, 193, 269, 157, 173, 523, 233, 157, 251, 193, 179, 383, 647, 311, 223, 317, 509, 457, 211, 503, 251, 479, 617, 1019, 347, 863, 827, 349, 389, 563, 601, 419, 367, 349, 449

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OFFSET

1,1

COMMENTS

a(n) is the second m (first m is A005235(n)) such that m > 1 and A002110(n)+m is prime. I guess every term of this sequence (compare the conjecture about A005235) is prime. I checked this conjecture for n < 373.

REFERENCES

R. K. Guy, Unsolved Problems in Number Theory, Section A2.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..200

MATHEMATICA

A005235[n_] := (For[m=2, !PrimeQ[Product[Prime[k], {k, n}]+m], m++ ]; m); a[n_] := (For[m=A005235[n]+1, !PrimeQ[Product[Prime[k], {k, n}]+m], m++ ]; m); Table[a[n], {n, 60}]

CROSSREFS

Cf. A005235, A002110.

Sequence in context: A191019 A106862 A027690 * A153118 A060449 A046140

Adjacent sequences: A087197 A087198 A087199 * A087201 A087202 A087203

KEYWORD

easy,nonn

AUTHOR

Farideh Firoozbakht, Aug 26 2003

STATUS

approved