A257393 -id:A257393 - cp's OEIS frontend

A257392 Number of ways of representing n as the sum of one or more consecutive nonprime numbers (A018252).

1, 2, 0, 0, 1, 2, 1, 0, 1, 1, 1, 2, 1, 0, 2, 1, 1, 1, 2, 3, 1, 1, 2, 1, 1, 1, 2, 3, 3, 1, 1, 2, 1, 2, 2, 1, 2, 1, 4, 2, 1, 2, 1, 1, 1, 4, 2, 0, 1, 4, 3, 3, 1, 2, 2, 2, 1, 2, 2, 2, 2, 0, 2, 4, 3, 2, 1, 3, 2, 3, 1, 2, 1, 0, 3, 4, 2, 2, 3, 3, 1, 3, 2, 1, 2, 3, 2, 2, 1, 1, 4, 2, 2, 1, 4, 5

Offset: 1

Juri-Stepan Gerasimov, Apr 21 2015

nonn

			a(2) = 2 because n = 2 itself is already a nonprime number (sum of 1 term), and 1 can in addition be written as A018252(1) + A018252(2), a sum of 2 consecutive nonprime numbers.

Cf. A051349, A053767, A018252, A166037, A166039, A242667, A257393.

A366976 Numbers that cannot be written as sum of two or more consecutive nonprimes.

Original entry on oeis.org

1, 2, 3, 4, 6, 7, 8, 9, 12, 13, 15, 16, 20, 21, 24, 25, 30, 32, 35, 40, 42, 44, 47, 48, 52, 56, 61, 66, 70, 72, 73, 80, 88, 93, 96, 98, 100, 107, 110, 119, 120, 140, 141, 144, 167, 174, 179, 186, 190, 196, 204, 205, 234, 236, 252, 253, 260, 275, 290, 292, 299, 303, 310, 312, 313

Offset: 1

Tamas Sandor Nagy, Dec 16 2023

nonn

The complement sequence of sums of two or more consecutive nonprime numbers.

			9 is a term because trying the sums of candidate consecutive nonprimes 1 + 4 = 5 != 9, 1 + 4 + 6 = 11 != 9, 4 + 6 = 10 != 9. All these sums miss the integer 9.
On the other hand, 23 is not a term because 23 = 6 + 8 + 9, which is the sum of three consecutive nonprime numbers.

Cf. A051349, A018252, A367021.

Primes in the sequence: A257393.

cp's OEIS Frontend

A257392 Number of ways of representing n as the sum of one or more consecutive nonprime numbers (A018252).

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