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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A051316 Euclid-Mullin sequence (A000945) with initial value a(1)=37 instead of a(1)=2.

Original entry on oeis.org

37, 2, 3, 223, 31, 7, 127, 5, 11, 17, 157, 390191, 23339, 29, 283, 73, 19, 47, 381735266856929, 149, 83, 71, 311, 9791, 4007, 3101629, 207541, 2591, 13, 2414519329, 107, 41, 53
Offset: 1

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Keywords

Comments

a(34) is a 95-digit prime.

Crossrefs

Programs

  • Mathematica
    a[1]=37; a[n_] := First[ Flatten[ FactorInteger[ 1+Product[ a[ j ], {j, n-1} ] ] ] ]; Array[a, 15]
  • PARI
    spf(n)=my(f=factor(n)[1, 1]); f; \\ A020639
    first(m)=my(v=vector(m)); v[1]=37; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v \\ Anders Hellström, Nov 26 2015

Formula

a(n) = A020639(1 + Product_{k=1..n-1} a(k)), a(1) = 37.

A051317 Euclid-Mullin sequence (A000945) with initial value a(1)=41 instead of a(1)=2.

Original entry on oeis.org

41, 2, 83, 3, 7, 47, 71, 29, 653, 5, 173, 23, 103058819, 11, 389, 73161901, 168593357, 13, 45613, 347, 211, 53, 400947612985987, 28837, 35111, 913011302795748880783905085999338914209329333652950191830525020998365540320068611
Offset: 1

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Crossrefs

Programs

  • Mathematica
    a[1]=41; a[n_] := First[ Flatten[ FactorInteger[ 1+Product[ a[ j ], {j, n-1} ] ] ] ]; Array[a, 15]
  • PARI
    spf(n)=my(f=factor(n)[1, 1]); f
    first(m)=my(v=vector(m)); v[1]=41; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v \\ Anders Hellström, Nov 26 2015

A051318 Euclid-Mullin sequence (A000945) with initial value a(1)=43 instead of a(1)=2.

Original entry on oeis.org

43, 2, 3, 7, 13, 53, 5, 6221671, 38709183810571, 139, 2801, 11, 17, 5471, 52662739, 23003, 30693651606209, 37, 1741, 1313797957, 887, 71, 7127, 109, 23, 97, 159227, 643679794963466223081509857, 103, 1079990819, 9539, 3143065813, 29, 3847, 89, 19, 577, 223
Offset: 1

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Keywords

Examples

			Product of first 28 terms +1 is 210102491806660945690525037461258737117339882568590700172677987135969766432980375 44232424110733238484973548134278212304532631, which is divisible by 103. Hence a(29)=103.
		

Crossrefs

Agrees with A000945 from 5th term. Cf. A000946, A005265, A005266.

Programs

  • Mathematica
    a[1]=43; a[n_] := First[ Flatten[ FactorInteger[ 1+Product[ a[ j ], {j, n-1} ] ] ] ]; Array[a, 15]
  • PARI
    spf(n)=factor(n)[1, 1]
    first(m)={my(v=vector(m),i,t=43);v[1]=43;for(i=2,m,v[i]=spf(t+1);t*=v[i];);v;} /* Anders Hellström, Jul 19 2015 */

Extensions

a(31)-a(38) from Robert Price, Jul 19 2015

A051319 Euclid-Mullin sequence (A000945) with initial value a(1)=47 instead of a(1)=2.

Original entry on oeis.org

47, 2, 5, 3, 17, 23971, 7, 4022094091, 3673, 11, 32915297, 21513736430048030802333949693291, 43, 349, 613, 37, 6767927, 59, 71249, 19, 4455467, 997, 181, 593, 681271, 113, 13, 1205224649, 1699, 533327, 1361, 29
Offset: 1

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Crossrefs

Programs

  • Mathematica
    a[1]=47; a[n_] := First[ Flatten[ FactorInteger[ 1+Product[ a[ j ], {j, 1, n-1} ] ] ] ]; Array[a, 10]
  • PARI
    spf(n)=factor(n)[1, 1]; \\ A020639
    first(m)=my(v=vector(m)); v[1]=47; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v \\ Anders Hellström, Nov 25 2015; corrected by Michel Marcus, Oct 10 2023

A051320 Euclid-Mullin sequence (A000945) with initial value a(1)=53 instead of a(1)=2.

Original entry on oeis.org

53, 2, 107, 3, 7, 11, 2620003, 707431, 1993, 4409, 131, 17, 5, 858127, 79, 163, 19, 46061, 31, 17707, 157, 43, 3135504913004354085487249, 9893869, 149, 1001472037, 16979051, 387853, 61, 13, 227, 41, 206779, 443, 37, 1709
Offset: 1

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Keywords

Crossrefs

Programs

  • Mathematica
    a[1]=53; a[n_] := First[ Flatten[ FactorInteger[ 1+Product[ a[ j ], {j, n-1} ] ] ] ]; Array[a, 15]
  • PARI
    spf(n)=my(f=factor(n)[1, 1]); f
    first(m)=my(v=vector(m)); v[1]=53; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v \\ Anders Hellström, Nov 26 2015

A051321 Euclid-Mullin sequence (A000945) with initial value a(1)=59 instead of a(1)=2.

Original entry on oeis.org

59, 2, 7, 827, 3, 13, 4583, 5, 610478010871, 61, 292658543, 4483, 47, 11, 31, 43, 16453, 41, 3671, 1982639, 628319, 841476613, 449, 997793, 73, 983, 53, 28475917, 19, 673
Offset: 1

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Author

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Crossrefs

Programs

  • Mathematica
    a[1]=59; 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]=59; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v \\ Anders Hellström, Dec 04 2015

Extensions

a(28)-a(48) from Robert Price, Jul 13 2015

A051322 Euclid-Mullin sequence (A000945) with initial value a(1)=61 instead of a(1)=2.

Original entry on oeis.org

61, 2, 3, 367, 7, 5, 1217, 17, 13, 59, 3271, 19, 11, 76938833, 337, 10711, 1021, 31, 83, 1290503, 15608141, 195648590992627, 109, 15983112328343713807564263439978033717550587578630760604057976854157331
Offset: 1

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Author

Keywords

Crossrefs

Programs

  • Mathematica
    a[1]=61; 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]=61; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v \\ Anders Hellström, Dec 04 2015

A051323 Euclid-Mullin sequence (A000945) with initial value a(1)=67 instead of a(1)=2.

Original entry on oeis.org

67, 2, 3, 13, 5227, 7, 5, 4637, 107, 23, 1889, 50929, 31, 1677554191669, 538282187, 59, 37, 17046661, 81088366624779421, 11, 6242880316142699576539967984792911, 73, 17, 1187, 101, 883, 3491, 47, 83, 852851, 317, 1493, 579707, 109, 1579145715181, 179, 1618489, 331
Offset: 1

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Author

Keywords

Crossrefs

Programs

  • Mathematica
    a[1]=67; 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]=67; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v \\ Anders Hellström, Dec 06 2015

Extensions

a(21)-a(38) from Robert Price, Jul 12 2015

A051325 Euclid-Mullin sequence (A000945) with initial value a(1)=73 instead of a(1)=2.

Original entry on oeis.org

73, 2, 3, 439, 7, 5, 6729871, 103, 23, 92581, 13, 19, 2453563465139998636061911, 739, 3167, 47356379285063777, 463, 3673, 2918137, 41, 17, 2307841395358410336056217199460000033494100011180619106269258300884070797073446703818111
Offset: 1

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Author

Keywords

Crossrefs

Programs

  • Mathematica
    a[1]=73; 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]=73; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v \\ Anders Hellström, Dec 06 2015

A051326 Euclid-Mullin sequence (A000945) with initial value a(1)=79 instead of a(1)=2.

Original entry on oeis.org

79, 2, 3, 5, 2371, 7, 39334891, 19, 29397438602292811, 43, 167, 839, 5839, 30402153456526009093473029504929376787635911, 241815479790331, 41, 180922657, 5303, 2389, 13, 31, 11
Offset: 1

Views

Author

Keywords

Comments

a(23) is a 122-digit prime.
a(5), a(7), a(9), a(14) and a(23) are all the product of the preceding terms + 1. - Robert Price, Jul 10 2015
a(32) requires factoring a composite 292 digit integer. - Robert Price, Sep 05 2021

Crossrefs

Programs

  • Mathematica
    a[1]=79; 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]=79; for(i=2, m, v[i]=spf(1+prod(j=1, i-1, v[j]))); v \\ Anders Hellström, Dec 06 2015

Formula

a(n) = A020639(1 + Product_{k=1..n-1} a(k)), a(1) = 79.
Previous Showing 31-40 of 52 results. Next