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A069496 Smaller member of a twin prime pair with a square sum. 14
17, 71, 881, 1151, 2591, 3527, 4049, 15137, 20807, 34847, 46817, 69191, 83231, 103967, 112337, 149057, 176417, 179999, 206081, 281249, 362951, 388961, 438047, 472391, 478241, 538721, 649799, 734471, 808991, 960497, 1080449, 1143071 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
All members of this sequence have digital root 8. - J. W. Helkenberg, Jul 24 2013
First bisection of A232878. - Gary Croft, Dec 05 2013
LINKS
Author?, Title? (no longer exists)
FORMULA
a(n) = (A037072(n)-2)/2.
a(n) = A118593(n) - 2. - Zerinvary Lajos, Jul 31 2006
EXAMPLE
71 is a term as the smaller member of the twin prime pair (71,73) as 71+73 = 144 = 12^2.
MAPLE
isa := n -> isprime(n) and isprime(n+2) and issqr(2*n+2):
select(isa, [$4..1000000]); # Peter Luschny, Jan 05 2020
MATHEMATICA
First/@Select[Partition[Prime[Range[9*10^4]], 2, 1], Differences[#]=={2} && IntegerQ[Sqrt[Total[#]]] &] (* Jayanta Basu, May 26 2013 *)
PROG
(PARI) t(n, p=3) = {while( p+2 < (p=nextprime( p+1 )) || n-->0, ); p-2}
for(n=1, 1e4, if(issquare(2*t(n)+2), print1(t(n), ", "))); \\ Altug Alkan, Mar 14 2016
CROSSREFS
Sequence in context: A290243 A320895 A288748 * A047978 A050524 A214530
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Mar 30 2002
EXTENSIONS
More terms from Sascha Kurz, Apr 01 2002
STATUS
approved

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Last modified July 17 16:16 EDT 2024. Contains 374377 sequences. (Running on oeis4.)