A348649 - OEIS

A348649

Odd numbers in the triangle of Stirling numbers of the second kind (A008277).

1, 1, 1, 1, 3, 1, 1, 7, 1, 1, 15, 25, 1, 1, 31, 65, 15, 1, 1, 63, 301, 21, 1, 1, 127, 1701, 1, 1, 255, 3025, 6951, 1, 1, 511, 34105, 42525, 22827, 45, 1, 1, 1023, 28501, 179487, 63987, 1155, 55, 1, 1, 2047, 611501, 159027, 22275, 1705, 1, 1, 4095, 261625, 7508501, 39325, 2431, 1

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OFFSET

1,5

COMMENTS

We take the odd values in A008277, as they appear, with duplicates.

For any n >= 1, the n-th row has A007306(n) terms.

LINKS

Rémy Sigrist, Table of n, a(n) for n = 1..10057 (rows for n = 1..331, flattened)

Rémy Sigrist, Logarithmic scatterplot of the first 35000 terms

Index entries for sequences related to Stirling numbers

EXAMPLE

As an irregular table, the first rows are:

1: 1;

2: 1, 1;

3: 1, 3, 1;

4: 1, 7, 1;

5: 1, 15, 25, 1;

6: 1, 31, 65, 15, 1;

7: 1, 63, 301, 21, 1;

8: 1, 127, 1701, 1;

9: 1, 255, 3025, 6951, 1;

10: 1, 511, 34105, 42525, 22827, 45, 1;

11: 1, 1023, 28501, 179487, 63987, 1155, 55, 1;

...

PROG

(PARI) row(n) = select(v -> v%2==1, vector(n, k, stirling(n, k, 2)))

CROSSREFS

See A014421, A014428, A014450, A014459 for similar sequences.

Cf. A007306, A008277, A348650 (even numbers).

Sequence in context: A102479 A228902 A053193 * A010273 A046143 A228035

Adjacent sequences: A348646 A348647 A348648 * A348650 A348651 A348652

KEYWORD

nonn,tabf

AUTHOR

Rémy Sigrist, Oct 27 2021

STATUS

approved