A145896 Values of m: where m^2 begins a run of consecutive squares satisfying r=p+4*m^2 with a sequence of primes

3, 6, 2, 1, 8, 4, 7, 1, 2, 1, 1, 1, 19, 1, 2, 1, 3, 1, 1, 1, 1, 1, 1, 1, 3, 3, 1, 1, 2, 1, 1, 2, 1, 4, 1, 1, 1, 1, 1, 2, 2, 1, 7, 3, 4, 1, 1, 2, 7, 1, 1, 2, 1, 1, 2, 1, 2, 1, 1, 2, 1, 1, 2, 1, 1, 2

Offset

1,1

Comments

Suggested by Farideh Firoozbakht's Puzzle 464 in Carlos Rivera's The Prime Puzzles & Problems Connection

Links

Table of n, a(n) for n=1..66.

Example

a(1)=3 because when m is 3 a sequence of three values of r end with prime 37; then r=1+4*1^1=5, prime; and r=1+4*2^2=17, prime; and r=1+4*3^2=37, prime (and the next value of m, 4, does not produce a prime because r=1+4*4^2=65). For this one value 1 is assumed prime.

Prog

(UBASIC) 10 'p464 20 N=1 30 A=3:S=sqrt(N) 40 B=N\A 50 if B*A=N then 100 60 A=A+2 70 if A<=S then 40 80 M=M+1:R=N+4*M^2:if R=prmdiv(R) and M<100 then print N; R; M:goto 80 90 if M>=1 then stop 100 M=0:N=N+2:goto 30

Crossrefs

A145897 A145898 A145741

Sequence in context: A176034 A367729 A255051 * A159963 A120907 A133358

Adjacent sequences: A145893 A145894 A145895 * A145897 A145898 A145899

Keyword

easy,nonn

Author

Enoch Haga, Oct 25 2008

Status

approved