A040047 -id:A040047 - cp's OEIS frontend

A068947 Square roots of A068809.

1, 2, 3, 7, 13, 17, 43, 63, 83, 167, 264, 313, 707, 836, 1667, 2236, 3114, 4472, 6833, 8167, 8937, 16667, 21886, 29614, 41833, 74833, 89437, 94863, 134164, 191833, 298327, 545793, 547613, 947617, 987917, 1643167, 3143167, 3162083, 5477133

Offset: 1

Francois Jooste (phukraut(AT)hotmail.com), Mar 15 2002

			13^2 = 169 = A068809(5), so a(5)=13.

Giovanni Resta, Table of n, a(n) for n = 1..80

Cf. A068809, A068948, A068949, A068950, A068952, A069324, A040047.

A007953 := proc(n) option remember: return add(d, d=convert(n, base, 10)): end: A068947 := proc(n) option remember: local k,p: if(n=1)then return 1: fi: k:=procname(n-1): p:=A007953(k^2): do k:=k+1: if(A007953(k^2)>p)then return k: fi: od: end: seq(A068947(n),n=1..20); # Nathaniel Johnston, May 04 2011

A069324 Primes in A068949.

Original entry on oeis.org

13, 19, 31, 43, 61, 67, 73, 79, 97, 103, 109, 127, 139, 157, 163, 181, 193, 199, 211

Offset: 1

Francois Jooste (phukraut(AT)hotmail.com), Mar 15 2002

Differs from A040047 at the 13th term. - Kevin Buzzard (k.buzzard(AT)imperial.ac.uk), Jun 20 2008

			a(4)=43 since the fourth prime in A068949 is 43.

Cf. A068809, A068949, A068952, A040047.

disum(n)= { local(resul) ; resul=0 ; while(n>0, resul += n%10 ; n = (n-n%10)/10 ; ) ; return(resul) ; }
A069324(maxs)= { local(ssqu,su) ; su=1 ; for(s=1,maxs, ssqu=s^2 ; if (disum(ssqu) > su, su=disum(ssqu) ; if( isprime(su), print1(su,",") ; ) ; ) ; ) ; }
A069324(200000000) ; \\ R. J. Mathar, May 19 2006

a(12) from R. J. Mathar, May 19 2006
a(13)-a(14) from Kevin Buzzard (k.buzzard(AT)imperial.ac.uk), Jun 20 2008
a(15)-a(19) from Giovanni Resta, Jun 27 2018

A040046 Primes p such that x^3 = 6 has a solution mod p.

Original entry on oeis.org

2, 3, 5, 7, 11, 17, 23, 29, 37, 41, 47, 53, 59, 71, 83, 89, 101, 107, 113, 131, 137, 139, 149, 163, 167, 173, 179, 181, 191, 197, 227, 233, 239, 241, 251, 257, 263, 269, 281, 293, 307, 311, 313, 317, 337, 347, 349

Offset: 1

N. J. A. Sloane

Complement of A040047 relative to A000040. - Vincenzo Librandi, Sep 13 2012

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Cf. A000040, A040047.

[p: p in PrimesUpTo(450) | exists(t){x : x in ResidueClassRing(p) | x^3 eq 6}]; // Vincenzo Librandi, Sep 11 2012

ok [p_]:=Reduce[Mod[x^3 - 6, p] == 0, x, Integers] =!= False;  Select[Prime[Range[180]], ok] (* Vincenzo Librandi, Sep 11 2012 *)

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A068947 Square roots of A068809.

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A069324 Primes in A068949.

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A040046 Primes p such that x^3 = 6 has a solution mod p.

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