login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A090101
Numbers n such that n and the 6 successive integers yield primes if substituted for x in polynomial 5x^2+5x+1.
7
1, 321, 63879, 6265151, 6921510, 9239188, 23156113, 26854544, 35917576, 45591317, 51307313, 52260254, 53855078, 71731838, 118305552, 124220571, 124234464, 150767861, 170448863, 192850264
OFFSET
1,2
EXAMPLE
a[15]=118305552 and the corresponding seven "polynomially consecutive" primes are: {69981018761651281, 69981019944706811, 69981021127762351, 69981022310817901, 69981023493873461, 69981024676929031, 69981025859984611}
MATHEMATICA
po[x_] := 5*x^2+5*x+1 Do[s=po[n]; s0=po[n]; s1=po[n+1]; s2=po[n+2]; s3=po[n+3]; s4=po[n+4]; s5=po[n+5]; s6=po[n+6]; If[IntegerQ[n/100000], Print[{n}]]; If[PrimeQ[s0]&&PrimeQ[s1]&&PrimeQ[s2]&&PrimeQ[s3]&&PrimeQ[s4]&&PrimeQ[s5] &&PrimeQ[s6], Print[{n, s0, s1, s2, s3, s4, s5, s6}]], {n, 1, 120000000}]
Select[Range[193*10^6], AllTrue[Table[5x^2+5x+1, {x, Range[#, #+6]}], PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Apr 02 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Dec 12 2003
EXTENSIONS
More terms from Don Reble, Dec 14 2003
STATUS
approved