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.

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A051312 Euclid-Mullin sequence (A000945) with initial value a(1)=19 instead of a(1)=2.

Original entry on oeis.org

19, 2, 3, 5, 571, 271, 457, 397, 1123, 23, 103, 42572757267735264511, 313, 17, 16013177, 7951, 1259, 41, 1531, 11, 83, 53, 67, 7, 21397, 13, 1619, 1274209367143, 433, 37, 491, 29, 658837, 135202080527, 163, 587, 31, 2797, 35286479
Offset: 1

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Crossrefs

Programs

  • Mathematica
    a[1]=19; a[n_] := First[ Flatten[ FactorInteger[ 1+Product[ a[ j ], {j, 1, n-1} ] ] ] ]; Array[a, 10]
  • PARI
    spf(n)=factor(n)[1, 1]
    first(m)=my(v=vector(m)); v[1]=19; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v; \\ Anders Hellström, Aug 31 2015

A051324 Euclid-Mullin sequence (A000945) with initial value a(1)=71 instead of a(1)=2.

Original entry on oeis.org

71, 2, 11, 3, 43, 201499, 67, 5, 487, 19, 967, 13, 131, 17, 3523392679146994953040171, 7, 633046028131441, 197, 1313225762816449, 22441, 29, 7039, 2357, 12264112894355231632110401532068053014661
Offset: 1

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Crossrefs

Programs

  • Mathematica
    a[1]=71; a[n_] := First[ Flatten[ FactorInteger[ 1+Product[ a[ j ], {j, 1, n-1} ] ] ] ]; Array[a, 10]
  • PARI
    spf(n)=my(f=factor(n)[1, 1]); f
    first(m)=my(v=vector(m)); v[1]=71; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v \\ Anders Hellström, Dec 04 2015

Extensions

a(24) from Robert Price, Jul 11 2015

A051330 Euclid-Mullin sequence (A000945) with initial value a(1)=97 instead of a(1)=2.

Original entry on oeis.org

97, 2, 3, 11, 19, 7, 461, 719, 5, 1411130344471, 139, 43, 36599, 1097, 17, 104370954301, 23, 13, 59, 41, 83, 196777201807603861, 569, 31, 149, 131, 7408846366410141253195388029, 29, 27017, 192228034594584553, 307, 2677, 73, 263, 389, 10463, 61, 47, 617, 743
Offset: 1

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Keywords

Crossrefs

Programs

  • Mathematica
    a[1]=97; a[n_] := First[ Flatten[ FactorInteger[ 1+Product[ a[ j ], {j, 1, n-1} ] ] ] ]; Array[a, 10]
  • PARI
    lpf(n)=factor(n)[1, 1]
    first(m)=my(v=vector(m)); v[1]=97; for(i=2, m, v[i]=lpf(1+prod(j=1, i-1, v[j]))); v; \\ Anders Hellström, Aug 31 2015

Extensions

a(34)-a(45) from Robert Price, Jul 20 2015

A093779 a(n) is the position of prime 3 in the Euclid-Mullin (EM) sequence of type A000945, if it were started with prime(n) instead of 2.

Original entry on oeis.org

2, 1, 4, 3, 4, 3, 4, 3, 4, 4, 3, 3, 4, 3, 4, 4, 5, 3, 3, 4, 3, 3, 4, 4, 3, 5, 3, 4, 3, 4, 3, 4, 4, 3, 5, 3, 3, 3, 4, 4, 4, 3, 4, 3, 4, 3, 3, 3, 4, 3, 4, 4, 3, 4, 4, 4, 5, 3, 3, 4, 3, 4, 3, 5, 3, 4, 3, 3, 4, 3, 5, 4, 3, 3, 3, 5, 5, 3, 4, 3, 4, 3, 4, 3, 3, 4, 4, 3, 5, 3, 4, 6, 3, 4, 3, 5, 4, 5, 3, 3, 3, 4, 5, 4, 3
Offset: 1

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Author

Labos Elemer, May 03 2004

Keywords

Examples

			p=3 arises first as n-th term for n=1,2,3,4 as follows: {3,2,7,43,13,53,5}, {2,3,7,43,13,53,5}, {7,2,3,43,13,53,5}, {5,2,11,3,331,19}, ... i.e., started at suitable initial primes;
p=2 arises always as 2nd or once as first term in case of various EM-sequences.
		

Crossrefs

A093780 a(n) is the smallest prime used as initial value for Euclid-Mullin (EM) sequence (of variant A000945), such that in the corresponding EM-sequence the p=3 prime arises at the n-th position.

Original entry on oeis.org

3, 2, 7, 5, 59, 479, 821, 1871, 17393, 43019, 284783, 1572149, 2737793, 32938853, 24254639
Offset: 1

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Author

Labos Elemer, May 03 2004

Keywords

Examples

			p=3 arises first as n-th term for n=1,2,3,4,...,9th as follows:
{3,2,7,43,13,53,5},{2,3,7,43,13,53,5},{7,2,3,43,13,53,5},
{5,2,11,3,331,19},{269,2,7,3767,3,42559567},{479,2,7,19,5,3},
{821,2,31,109,7,509,3},{1871,2,19,7,37,13,23,3},
{17393,2,43,37,7,4129,13,5,3},
		

Crossrefs

Extensions

More terms from David Wasserman, Apr 12 2007

A093781 a(n) is the position of the prime 5 in the Euclid-Mullin (EM) sequence of type A000945, if it were started with prime(n) instead of 2.

Original entry on oeis.org

7, 7, 1, 7, 18, 10, 3, 4, 11, 7, 8, 8, 10, 7, 3, 13, 8, 6, 7, 8, 6, 4, 7, 8, 9, 4, 6, 3, 4, 11, 5, 8, 3, 4, 4, 8, 8, 13, 3, 10, 21, 15, 6, 8, 3, 4, 13, 5, 3, 4, 8, 14, 6, 10, 3, 6, 12, 6, 10, 6, 6, 13, 8, 4, 6, 3, 11, 5, 3, 4, 13, 6, 10, 8, 4, 26, 8, 7, 11, 4, 7, 10, 7, 5, 4, 7, 16, 8, 7, 9, 3, 5, 5, 6
Offset: 1

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Author

Labos Elemer, May 04 2004

Keywords

Comments

a(38) = 13 because prime(38) = 163 and the corresponding EM sequence is {163, 2, 3, 11, 7, 75307, 3931, 5399, 3041, 409, 179, 92958641873, 5, 2003, ...}, where 5 appears at the 13th position. - David Wasserman, Apr 19 2007

Crossrefs

Programs

  • PARI
    em(i) = local(p, c, n, f, q); p = prime(i); if (p == 5, return(1)); c = 1; n = p; while (1, c++; f = factor(n + 1, 2^31 - 1); q = f[1, 1]; if (!isprime(q), f = factor(n + 1); q = f[1, 1]); if (q == 5, return(c)); n *= q); \\ David Wasserman, Apr 19 2007

Extensions

More terms from David Wasserman, Apr 19 2007

A051310 Euclid-Mullin sequence (A000945) with initial value a(1)=13 instead of a(1)=2.

Original entry on oeis.org

13, 2, 3, 79, 6163, 7, 1601, 11, 137, 5, 199, 151, 263, 983, 31, 83, 30187890723499, 23847817657, 37, 67, 9661, 251, 73, 1214623152057970133, 24597089626521443731307390760915220105471840174452030562332559181845834101711082531
Offset: 1

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Crossrefs

Programs

  • Mathematica
    a[1]=13; a[n_] := First[ Flatten[ FactorInteger[ 1+Product[ a[ j ], {j, 1, n-1} ] ] ] ]; Array[a, 10]
  • PARI
    spf(n)=factor(n)[1,1]
    first(m)=my(v=vector(m)); v[1]=13; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v; \\ Anders Hellström, Aug 22 2015

A051311 Euclid-Mullin sequence (A000945) with initial value a(1)=17 instead of a(1)=2.

Original entry on oeis.org

17, 2, 5, 3, 7, 3571, 31, 395202571, 13, 29, 137, 23, 97, 1896893, 34138453466895150823580146142491, 4639, 61, 181, 43, 19, 11, 59, 25292522503108044617, 4909, 18305191, 467
Offset: 1

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Author

Keywords

Crossrefs

Programs

  • Mathematica
    a[1]=17; a[n_] := First[ Flatten[ FactorInteger[ 1+Product[ a[ j ], {j, 1, n-1} ] ] ] ]; Array[a, 10]
  • PARI
    spf(n)=factor(n)[1,1]
    first(m)=my(v=vector(m)); v[1]=17; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v; \\ Anders Hellström, Aug 22 2015

A051313 Euclid-Mullin sequence (A000945) with initial value a(1)=23 instead of a(1)=2.

Original entry on oeis.org

23, 2, 47, 3, 13, 84319, 7109609443, 463, 23403050994721829453179, 7, 5, 57367, 239, 40237, 10575444619218059847586376042094152838881224222904607376771, 31333, 742759, 9444637217
Offset: 1

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Author

Keywords

Crossrefs

Programs

  • Mathematica
    a[1]=23; a[n_] := First[ Flatten[ FactorInteger[ 1+Product[ a[ j ], {j, 1, n-1} ] ] ] ]; Array[a, 10]
  • PARI
    spf(n)=factor(n)[1, 1]
    first(m)=my(v=vector(m)); v[1]=23; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v; \\ Anders Hellström, Nov 22 2015

Extensions

a(18)-a(37) from Robert Price, Jul 17 2015

A051314 Euclid-Mullin sequence (A000945) with initial value a(1)=29 instead of a(1)=2.

Original entry on oeis.org

29, 2, 59, 3, 10267, 7, 5, 3689035771, 19, 396029, 489851, 2971, 179, 13, 4441009, 419, 79, 53, 3109, 538004633, 138285071, 241, 263, 443, 11, 17, 951837583454247922680798591029699, 739, 43, 181, 131, 3257, 31, 2237
Offset: 1

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Author

Keywords

Crossrefs

Programs

  • Mathematica
    a[1]=29; a[n_] := First[ Flatten[ FactorInteger[ 1+Product[ a[ j ], {j, 1, n-1} ] ] ] ]; Array[a, 10]
  • PARI
    spf(n)=factor(n)[1, 1]
    first(m)=my(v=vector(m)); v[1]=29; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v; \\ Anders Hellström, Nov 21 2015
Previous Showing 11-20 of 100 results. Next