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A154301 Primes of the form (1+2+...+m)/75 = A000217(m)/75. 3
17, 37, 149, 151 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Original definition: "Primes of the form : 1/x+2/x+3/x+4/x+5/x+6/x+7/x+..., x=75."

The corresponding m-values are m=50,74,149,150. It is clear that for m>2*75, T(m)/75 = m(m+1)/150 cannot be a prime, since then each factor in the numerator is larger than the denominator. See A154304 for further comments and PARI code. - M. F. Hasler, Jan 06 2013

LINKS

Table of n, a(n) for n=1..4.

MATHEMATICA

lst={}; s=0; Do[s+=n/75; If[Floor[s]==s, If[PrimeQ[s], AppendTo[lst, s]]], {n, 0, 3*9!}]; lst

PROG

(PARI) d=75*2; for(m=1, 999, (m^2+m)%d==0&isprime((m^2+m)/d)&print1(m", ")) \\ print the m-values(!) - use A154304(75) to get A154301 as a vector. \\ - M. F. Hasler, Jan 06 2013

CROSSREFS

Cf. A057570, A154293, A154296 - A154304.

Sequence in context: A269240 A060429 A052292 * A057185 A157467 A093343

Adjacent sequences:  A154298 A154299 A154300 * A154302 A154303 A154304

KEYWORD

nonn,fini,full,easy,bref

AUTHOR

Vladimir Joseph Stephan Orlovsky, Jan 06 2009

EXTENSIONS

Keywords fini,full added by R. J. Mathar, Aug 15 2010

Edited by M. F. Hasler, Jan 06 2013

STATUS

approved

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Last modified June 16 21:55 EDT 2021. Contains 345080 sequences. (Running on oeis4.)