|
Search: id:A052034
|
|
|
| A052034 |
|
Primes such that the sum of the squares of their digits is also a prime. |
|
+0
9
|
|
| 11, 23, 41, 61, 83, 101, 113, 131, 137, 173, 179, 191, 197, 199, 223, 229, 311, 313, 317, 331, 337, 353, 373, 379, 397, 401, 409, 443, 449, 461, 463, 467, 601, 641, 643, 647, 661, 683, 719, 733, 739, 773, 797, 829, 863, 883, 911, 919, 937, 971, 977, 991, 997, 1013
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
Primes p such that the sum of the squared digits of p is a prime q. For the values of q see A109181.
|
|
REFERENCES
|
Charles W. Trigg, Journal of Recreational Mathematics, Vol. 20(2), 1988.
"Hands On Numbers Count", Personal Computer World, 1997, p. 290.
|
|
EXAMPLE
|
E.g. p=23 is OK because q=2^2+3^2=13 is a prime.
E.g. 9431 -> 9^2+4^2+3^2+1^2 = 107 and prime.
|
|
MAPLE
|
a:=proc(n) local nn, L: nn:=convert(n, base, 10): L:=nops(nn): if isprime(n)= true and isprime(add(nn[j]^2, j=1..L))=true then n else end if end proc: seq(a(n), n=1..1000); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Jan 08 2008
|
|
CROSSREFS
|
Cf. A052035, A003132, A108662, A109181.
Sequence in context: A094376 A086524 A060915 this_sequence A077041 A068842 A146451
Adjacent sequences: A052031 A052032 A052033 this_sequence A052035 A052036 A052037
|
|
KEYWORD
|
nonn,base
|
|
AUTHOR
|
Patrick De Geest (pdg(AT)worldofnumbers.com), Dec 15 1999.
|
|
EXTENSIONS
|
Edited by N. J. A. Sloane (njas(AT)research.att.com), Dec 15 2007 and again on Dec 05 2008 at the suggestion of Zak Seidov
|
|
|
Search completed in 0.002 seconds
|
