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.

Showing 1-5 of 5 results.

A088292 Smallest prime in which the digit string can be partitioned in n+1 parts (0 parts allowed) such that the sum of the first n parts = the (n+1)th one.

Original entry on oeis.org

11, 101, 1427, 10067, 100517, 1000427, 10000247, 100001147, 1000000427, 10000001057, 100000000427, 1000000002227, 10000000002227, 100000000000067, 1000000000011227, 10000000000002137, 100000000000000337
Offset: 0

Views

Author

Amarnath Murthy, Sep 30 2003

Keywords

Examples

			a(1) = 11, 1 = 1.
a(2) = 167, 1+6 = 7
a(3) = 1427, 1+4+2 = 7.
		

Crossrefs

Extensions

More terms from David Wasserman, Aug 04 2005

A088293 Smallest prime in which the digit string can be partitioned into n+1 parts (only nonzero parts allowed) such that the sum of the first n parts = the (n+1)th one.

Original entry on oeis.org

11, 167, 1427, 12227, 111227, 11117213, 11111117, 1111111411, 11111111917, 111111118319, 1111111111717, 11111111132923, 111111111114823, 1111111111113823, 11111111111111923, 111111111111112319, 1111111111111116223, 11111111111111121119, 111111111111111111523
Offset: 1

Views

Author

Amarnath Murthy, Sep 30 2003

Keywords

Examples

			a(1) = 11, 1 = 1.
a(2) = 167, 1+6 = 7
a(3) = 1427, 1+4+2 = 7.
a(4) = 12227, 1+2+2+2 = 7.
a(5) = 111227, 1+1+1+2+2 = 7.
a(6) = 11117213, 1+1+1+1+7+2 = 13.
a(7) = 11111117, 1+1+1+1+1+1+1 = 7.
a(8) = 1111111411, 1+1+1+1+1+1+1+4 = 11.
		

Crossrefs

Extensions

a(6)-a(8) from Randy L. Ekl, Jan 08 2017
Offset corrected by Omar E. Pol, Jan 09 2017
a(9)-a(19) from Giovanni Resta, Apr 24 2017

A088294 Primes in which the digit string can be partitioned into three parts such that third (least significant) part is the product of the first two.

Original entry on oeis.org

199, 313, 919, 7321, 7963, 11717, 11777, 12323, 13339, 14747, 15959, 16363, 17117, 17351, 18181, 18787, 21121, 23369, 27127, 29129, 29387, 31393, 31751, 31957, 32369, 32987, 39139, 41141, 47147, 51151, 59159, 71171, 81181, 87187, 89189
Offset: 1

Views

Author

Amarnath Murthy, Sep 30 2003

Keywords

Comments

Primes in A280635. - Randy L. Ekl, Jan 09 2017

Examples

			17351 is a member as it can be partitioned as (17, 3, 51) and 17*3 = 51.
		

Crossrefs

Extensions

More terms from David Wasserman, Aug 04 2005
Offset changed to 1 by Michel Marcus, Jan 08 2017

A067860 Primes which are the concatenation of numbers n_1, n_2, n_3, in that order, with n_1 + n_2 = n_3 (leading zeros are forbidden for nonzero n_i).

Original entry on oeis.org

101, 167, 257, 347, 617, 5813, 7411, 8311, 8513, 9413, 9817, 10111, 10313, 11213, 11617, 12113, 12517, 12829, 13417, 13619, 14243, 14519, 14923, 15217, 15823, 15859, 16061, 16319, 17623, 18119, 18523, 19423, 19697, 20323, 20929, 21517, 22123, 23537, 23629, 23831, 24547
Offset: 1

Views

Author

Joseph L. Pe, Feb 15 2002

Keywords

Examples

			167 is the concatenation of 1, 6, 7 and 1+6 = 7.
		

Crossrefs

See A088291 for another version.

Programs

  • PARI
    is(n)=if(n==101, return(1)); my(d=digits(n)); for(i=1,#d-2, for(j=i+1,#d-1, if(digits(fromdigits(d[1..i])+fromdigits(d[i+1..j]))==d[j+1..#d] && (d[i+1] || i==j+1), return(isprime(n))))); 0
    select(is,primes(10^4)) \\ Charles R Greathouse IV, Sep 21 2015
    
  • PARI
    \\ See PARI link. David A. Corneth, Mar 06 2021

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Jun 11 2002
Data corrected and more terms from David A. Corneth, Mar 06 2021

A088295 Smallest prime in which the digit string can be partitioned in n+1 parts such that the product of the first n parts = the (n+1)th one.

Original entry on oeis.org

11, 199, 3319, 11177, 111919, 1111339, 11133119, 111111199, 1111111919, 11111113319, 1111111139381, 1111111111177, 11111111113139, 111111111113113, 1111111111113319, 11111111311111319, 111111111311111113
Offset: 0

Views

Author

Amarnath Murthy, Sep 30 2003

Keywords

Examples

			a(3) = 3319 because it can be partitioned as 3, 3, 1, 9 and 3*3*1 = 9.
		

Crossrefs

Extensions

More terms from David Wasserman, Aug 08 2005
Showing 1-5 of 5 results.