A350169 Write 1st prime and decrement 0 times, then write 2nd prime and decrement once, write 3rd prime and decrement twice, write 4th prime and decrement 3 times, etc ...

2, 3, 2, 5, 4, 3, 7, 6, 5, 4, 11, 10, 9, 8, 7, 13, 12, 11, 10, 9, 8, 17, 16, 15, 14, 13, 12, 11, 19, 18, 17, 16, 15, 14, 13, 12, 23, 22, 21, 20, 19, 18, 17, 16, 15, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26

Offset

1,1

References

J.-P. Delahaye, Des suites fractales d’entiers, Pour la Science, No. 531 January 2022. Sequence b) p. 82.

Links

Table of n, a(n) for n=1..78.

Example

As a triangle, this begins:
[2]
[3, 2]
[5, 4, 3]
[7, 6, 5, 4]
[11, 10, 9, 8, 7]
[13, 12, 11, 10, 9, 8]
[17, 16, 15, 14, 13, 12, 11]
[19, 18, 17, 16, 15, 14, 13, 12]
[23, 22, 21, 20, 19, 18, 17, 16, 15]
...

Maple

a:=[];
for n from 1 to 16 do
t1:=[seq(ithprime(n)-i, i=0..n-1)];
lprint(t1);
a:=[op(a), op(t1)];
od:
a; # N. J. A. Sloane, Dec 18 2021

Prog

(Python)
from sympy import prime
from itertools import count, islice
def agen():
    for i in count(1):
        pi = prime(i)
        yield from range(pi, pi-i, -1)
print(list(islice(agen(), 69))) # Michael S. Branicky, Dec 18 2021

Crossrefs

Cf. A000040.

Sequence in context: A075861 A205706 A141658 * A089587 A278327 A067316

Adjacent sequences: A350166 A350167 A350168 * A350170 A350171 A350172

Keyword

nonn,tabf

Author

Michel Marcus, Dec 18 2021

Status

approved