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A227994 Primes that are the sum of the squares of three integers that form an arithmetic sequence with difference 7. 1
461, 773, 1181, 1973, 2621, 6173, 7901, 9173, 11261, 21773, 29501, 37061, 44021, 50021, 51581, 54773, 58061, 66701, 68501, 72173, 75941, 81773, 85781, 96221, 109541, 118901, 126173, 143981, 204461, 210773, 220421, 233621, 236981, 254141, 279173, 286541, 328781, 336773 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primes of the form 3k^2 + 42k + 245. - Charles R Greathouse IV, Aug 14 2013

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

461 is a term since 4^2 + 11^2 + 18^2 = 461;

773 is a term since 8^2 + 15^2 + 22^2 = 773;

1181 is a term since 12^2 + 19^2 + 26^2 = 1181;

1973 is a term since 18^2 + 25^2 + 32^2 = 1973.

MAPLE

for x in range(1, 2000): b=x**2  : c= (x+7)**2: d=(x+14)**2:e=(b+c+d): print x, e

MATHEMATICA

Select[Table[Total[(n+{0, 7, 14})^2], {n, 500}], PrimeQ] (* Harvey P. Dale, Jun 10 2021 *)

PROG

(PARI) for(n=1, 1e3, if(isprime(t=3*(n+7)^2+98), print1(t", "))) \\ Charles R Greathouse IV, Aug 14 2013

CROSSREFS

Subsequence of A085317. - Michel Marcus, Apr 01 2019

Sequence in context: A252535 A264242 A107973 * A142832 A277989 A138956

Adjacent sequences:  A227991 A227992 A227993 * A227995 A227996 A227997

KEYWORD

nonn,changed

AUTHOR

Will Gosnell, Aug 14 2013

EXTENSIONS

a(14)-a(38) from Charles R Greathouse IV, Aug 14 2013

Name clarified by Jon E. Schoenfield, Apr 01 2019

STATUS

approved

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Last modified June 17 17:05 EDT 2021. Contains 345085 sequences. (Running on oeis4.)