cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Previous Showing 11-19 of 19 results.

A094487 Primes p such that 2^j+p^j are primes for j=0,1,2,4.

Original entry on oeis.org

3, 5, 17, 4517, 5477, 5867, 7457, 8537, 13877, 16067, 22697, 27917, 56477, 59357, 90437, 97577, 101747, 118247, 122207, 124247, 135467, 139457, 140417, 153947, 208697, 247067, 267677, 306947, 419927, 470087, 489407, 520547, 529577, 540347
Offset: 1

Views

Author

Labos Elemer, Jun 01 2004

Keywords

Examples

			For j=0 1+1=2 is prime; also terms should be lesser-twin-primes
because of p^1+2^1=p+2=prime; 3rd and 4th conditions are as
follows: prime=p^2+4 and prime=16+p^4.
		

Crossrefs

Programs

  • Mathematica
    {ta=Table[0, {100}], u=1}; Do[s0=2;s1=Prime[j]+2;s2=4+Prime[j]^2;s4=16+Prime[j]^4; If[PrimeQ[s0]&&PrimeQ[s1]&&PrimeQ[s2]&&PrimeQ[s4], Print[{j, Prime[j]}];ta[[u]]=Prime[j];u=u+1], {j, 1, 1000000}]
    Select[Prime[Range[45000]],AllTrue[{2+#,4+#^2,16+#^4},PrimeQ]&] (* Harvey P. Dale, Sep 18 2022 *)

A094489 Primes p such that 2^j+p^j are primes for j=0,1,4,32.

Original entry on oeis.org

59, 5417, 19079, 33827, 136949, 181871, 242519, 284897, 421607, 452537, 552401, 598187, 962681, 1068251, 1081979, 1163231, 1317761, 1760279, 1801361, 1891499, 1895081, 1919459, 2056907, 2131601, 2427461, 2557601, 2579177, 2826737
Offset: 1

Views

Author

Labos Elemer, Jun 01 2004

Keywords

Examples

			For j=0 1+1=2 is prime; also terms should be lesser-twin-primes
because of p^1+2^1=p+2=prime; 3rd and 4th conditions are as
follows: prime=p^4+16 and prime=2^32+p^32.
		

Crossrefs

Programs

  • Mathematica
    {ta=Table[0, {100}], u=1}; Do[s0=2;s1=Prime[j]+2;s2=4+Prime[j]^2;s8=2^32+Prime[j]^32; If[PrimeQ[s0]&&PrimeQ[s1]&&PrimeQ[s2]&&PrimeQ[s8], Print[{j, Prime[j]}];ta[[u]]=Prime[j];u=u+1], {j, 1, 1000000}]
    Select[Prime[Range[210000]],AllTrue[{2+#,16+#^4,2^32+#^32},PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jun 13 2015 *)

A094490 Primes p such that 2^j+p^j are primes for j=0,2,4,64.

Original entry on oeis.org

37, 1423, 8537, 61333, 397963, 419927, 699217, 1151603, 1156823, 1210793, 1746923, 1809163, 1915477, 2012113, 2713127, 3617683, 4001567, 4192033, 4760117, 4768133, 5099623, 5432153, 5801737, 5909737, 5924833, 6118157
Offset: 1

Views

Author

Labos Elemer, Jun 01 2004

Keywords

Examples

			For j=0 1+1=2 is prime; other conditions are:
because of p^2+4==prime; 3rd and 4th conditions are as
follows: prime=p^4+16 and prime=2^64+p^64.
		

Crossrefs

Programs

  • Mathematica
    {ta=Table[0, {100}], u=1}; Do[s0=2;s2=4+Prime[j]^2;s4=16+Prime[j]^4;s64=2^64+Prime[j]^64 If[PrimeQ[s0]&&PrimeQ[s2]&&PrimeQ[s4]&&PrimeQ[s64], Print[{j, Prime[j]}];ta[[u]]=Prime[j];u=u+1], {j, 1, 1000000}]
    Select[Prime[Range[500000]],AllTrue[Table[2^j+#^j,{j,{0,2,4,64}}], PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Mar 29 2015 *)

A094492 Primes p such that 2^j+p^j are primes for j=0,1,4,16.

Original entry on oeis.org

179, 461, 521, 1877, 4259, 9767, 30389, 33071, 33329, 93701, 120077, 124247, 145547, 163481, 181871, 245627, 344171, 345731, 487427, 492671, 522281, 598187, 700199, 709739, 736061, 769259, 833717, 955709, 966869, 1009649, 1030739
Offset: 1

Views

Author

Labos Elemer, Jun 01 2004

Keywords

Comments

Primes of 2^j+p^j form are a generalization of Fermat-primes. 1^j is replaced by p^j. This is strongly supported by the observation that corresponding j-exponents are apparently powers of 2 like for the 5 known Fermat primes. See A094473-A094491.

Examples

			For j=0 1+1=2 is prime; other conditions are:
because of p^1+2=prime; 3rd and 4th conditions are as
follows: prime=p^4+16 and prime=65536+p^16.
		

Crossrefs

Programs

  • Mathematica
    {ta=Table[0, {100}], u=1}; Do[s0=2;s1=2+Prime[j]^1;s8=16+Prime[j]^4;s16=65536+Prime[j]^16 If[PrimeQ[s0]&&PrimeQ[s4]&&PrimeQ[s8]&&PrimeQ[s128], Print[{j, Prime[j]}];ta[[u]]=Prime[j];u=u+1], {j, 1, 1000000}]
    With[{j={0,1,4,16}},Select[Prime[Range[81000]],And@@PrimeQ[2^j+#^j]&]] (* Harvey P. Dale, Oct 17 2011 *)

A094316 Primes p for which 2^j+p^j is also prime for j in {0,2,8,512}.

Original entry on oeis.org

13, 4133, 1831343, 2320583, 3828673, 9173893, 23658377, 24037537, 42489677, 56253203, 78222863, 96325093, 99846337, 110453773, 110468653, 117748427, 122173187, 130937467, 138072163, 146981537, 174978913, 184050553, 186927817
Offset: 1

Views

Author

Labos Elemer, Jun 02 2004

Keywords

Examples

			Smallest such prime is 13 and the relevant four primes are
2, 173, 815730977 and a 571-digit prime.
		

Crossrefs

Programs

  • Mathematica
    {ta=Table[0, {100}], u=1}; {exponents, {a, b, c, d}={0, 2, 8, 512}} Do[s0=Prime[j]^a+2^a;s1=Prime[j]^b+2^b;s2=Prime[j]^c+2^c;s3=Prime[j]^d+2^d; If[PrimeQ[s0]&&PrimeQ[s1]&&PrimeQ[s2]&&PrimeQ[s3], Print[{j, Prime[j]}];ta[[u]]=Prime[j];u=u+1], {j, 1, 1000000}] ta

Extensions

a(6)-a(23) from Donovan Johnson, Oct 12 2008

A094478 Primes of form 2^j + 59^j.

Original entry on oeis.org

2, 61, 12117377, 464798130469793589516643498190087912509935907401081390977
Offset: 1

Views

Author

Labos Elemer, Jun 01 2004

Keywords

Comments

The number j must be zero or a power of 2. Checked j being powers of two through 2^21. Thus a(5) > 10^2900000. Primes of this magnitude are rare (about 1 in 6.7 million), so chance of finding one is remote with today's computer algorithms and speeds. - Robert Price, Apr 28 2013

Examples

			j=0: p=1+1=2;
j=1: p=2+59=61;
j=4: p=16+12117361=12117377;
j=32: p=2^32+59^32=464798130469793589516643498190087912509935907401081390977;
the j exponents are powers of 2.
		

Crossrefs

A094483 Primes of form 2^j + 179^j.

Original entry on oeis.org

2, 181, 1026625697, 1110832290554380967776058484990830657
Offset: 1

Views

Author

Labos Elemer, Jun 01 2004

Keywords

Comments

No additional terms through j=1000. - Harvey P. Dale, Apr 24 2013
The number j must be zero or a power of 2. Checked j being powers of two through 2^19. Thus a(5) > 10^2300000. Primes of this magnitude are rare (about 1 in 5.4 million), so chance of finding one is remote with today's computer algorithms and speeds. - Robert Price, May 05 2013

Crossrefs

Programs

  • Mathematica
    Select[Table[2^j+179^j, {j,0,30}], PrimeQ] (* Harvey P. Dale, Apr 24 2013 *)

A094484 Primes of form 2^j + 461^j.

Original entry on oeis.org

2, 463, 45165175457, 4161163747708008324368372925882377717624897
Offset: 1

Views

Author

Labos Elemer, Jun 01 2004

Keywords

Comments

The number j must be zero or a power of 2. Checked j being powers of two through 2^19. Thus a(5) > 10^2700000. Primes of this magnitude are rare (about 1 in 6.4 million), so chance of finding one is remote with today's computer algorithms and speeds. - Robert Price, Apr 29 2013

Examples

			The relevant exponents are powers of 2: 0, 1, 4, 16; a(4) = 65536+461^16 = 4161163747708008324368372925882377717624897.
		

Crossrefs

A094493 Primes p such that 2^j+p^j are primes for j=0,1,2,16.

Original entry on oeis.org

43577, 84317, 93887, 108377, 124247, 346667, 379997, 431867, 461297, 579197, 681257, 819317, 863867, 889037, 1143047, 1146797, 1271027, 1306817, 1518707, 1775867, 1926647, 1948517, 2119937, 2177447, 2348807, 2491607, 2604557
Offset: 1

Views

Author

Labos Elemer, Jun 01 2004

Keywords

Comments

Primes of 2^j+p^j form are a generalization of Fermat-primes. 1^j is replaced by p^j. This is strongly supported by the observation that corresponding j-exponents are apparently powers of 2 like for the 5 known Fermat primes. See A094473-A094491.

Examples

			For j=0: 1+1=2 is prime; other conditions are:
because of p^1+2=prime; 3rd and 4th conditions are as
follows: prime=p^2+4 and prime=65536+p^16.
		

Crossrefs

Programs

  • Mathematica
    {ta=Table[0, {100}], u=1}; Do[s0=2;s1=2+Prime[j]^1;s2=4+Prime[j]^2;s16=65536+Prime[j]^16 If[PrimeQ[s0]&&PrimeQ[s1]&&PrimeQ[s2]&&PrimeQ[s16], Print[{j, Prime[j]}];ta[[u]]=Prime[j];u=u+1], {j, 1, 1000000}]
    Select[Prime[Range[2*10^5]],AllTrue[Table[2^k+#^k,{k,{0,1,2,16}}],PrimeQ]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 05 2021 *)
Previous Showing 11-19 of 19 results.