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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A133372 Semiprimes expressible as the sum of (at least two) consecutive semiprimes in at least 1 way.

Original entry on oeis.org

10, 15, 25, 33, 39, 51, 58, 69, 77, 82, 85, 91, 93, 94, 95, 106, 115, 118, 122, 123, 133, 134, 142, 143, 146, 155, 158, 159, 161, 166, 177, 178, 185, 187, 201, 205, 209, 213, 215, 217, 219, 221, 226, 235, 237, 249, 253, 254, 262, 267, 274, 278, 291, 295, 298
Offset: 1

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Author

Jonathan Vos Post, Dec 21 2007

Keywords

Comments

This is to A067377 as A001358 is to A000040.

Examples

			a(1) = 10 = 4 + 6 = 2 * 5.
a(2) = 15 = 6 + 9 = 3 * 5.
a(3) = 25 = 6 + 9 + 10 = 5^2.
		

Crossrefs

Formula

A001358 INTERSECTION A135363.

Extensions

More terms from R. J. Mathar, Jan 13 2008

A336581 Mersenne exponents whose corresponding prime can be expressed as the sum of at least two consecutive primes.

Original entry on oeis.org

5, 7, 13, 17, 61
Offset: 1

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Author

Michel Marcus, Aug 30 2020

Keywords

Comments

127 is a term.

Examples

			5 is a term because 2^5-1 = 7 + 11 + 13.
17 is a term because 2^17-1 = 43669 + 43691 + 43711.
		

Crossrefs

Cf. A000043 (Mersenne exponents), A000668, A050936, A067377.

Programs

  • PARI
    isok(m) = my(p=2^m-1); isprime(p) && isA050936(p);

A350335 Primes expressible as the sum of (at least two) consecutive primes in at least 7 ways.

Original entry on oeis.org

3634531, 27411611, 28127521, 28445689, 48205429, 54604973, 56857523, 63461429, 70734089, 72087167, 75489781, 82183951, 83020733, 89752433, 92712023, 94026311, 100925263, 111282419, 137392361, 163506407, 164711999, 194039771, 195327179, 196364899, 196876789
Offset: 1

Views

Author

Jon E. Schoenfield, Dec 25 2021

Keywords

Comments

Subsequence of A350334.

Examples

			3634531 is a term because it is a prime and
   3634531 = Sum_{j=42997..43003} prime(j)
           = Sum_{j=15749..15769} prime(j)
           = Sum_{j=7294..7342} prime(j)
           = Sum_{j=7032..7082} prime(j)
           = Sum_{j=3397..3509} prime(j)
           = Sum_{j=165..1003} prime(j)
           = Sum_{j=65..995} prime(j).
		

Crossrefs

Previous Showing 11-13 of 13 results.