A369349 The number of terms beyond the first term in the series described in A369348 but when starting at n.

12, 0, 0, 1, 2, 11, 0, 0, 1, 17, 1, 3, 1, 3, 3, 0, 2, 1, 2, 10, 16, 11, 0, 0, 11, 6, 0, 16, 0, 0, 1, 0, 2, 9, 2, 0, 0, 10, 7, 9, 2, 0, 2, 10, 1, 15, 0, 10, 10, 1, 15, 1, 3, 7, 15, 1, 6, 9, 0, 0, 0, 9, 0, 0, 1, 2, 2, 9, 9, 0, 0, 0, 2, 9, 0, 8, 9, 0, 1, 0, 0, 8, 0, 2, 9, 5, 6, 14, 1, 8, 1, 6, 3, 7

Offset

1,1

Comments

In the first 250000 terms the largest value is a(203564) = 30. See the examples.

See A369353 for the numbers that terminate the series with lengths >= 1.

Links

Scott R. Shannon, Table of n, a(n) for n = 1..10000

Example

a(1) = 12. See A369348 for further information.
a(2) = 0 as there is no number k such that k - 2 = sopfr(k) + sopfr(2).
a(5) = 2 as the series when starting at 5 is 5, 18, 36, and there is no number k such that k - 36 = sopfr(k) + sopfr(36).
a(203564) = 30 as the series when starting at 203564 is 203564, 279917, 305772, 306383, 307737, 309072, 618538, 1237084, 1547240, 1549668, 1555427, 1689623, 1850460, 1897986, 1978513, 2170033, 2300849, 2307769, 2313234, 4629862, 6952637, 6966959, 7000937, 8032504, 9080469, 9125207, 9266466, 14110329, 28220667, 37702139, 37817849, and there is no number k such that k - 37817849 = sopfr(k) + sopfr(37817849).

Crossrefs

Cf. A369348, A001414, A369350, A369351, A369352, A369353.

Sequence in context: A104203 A242240 A225341 * A368816 A004012 A360223

Adjacent sequences: A369346 A369347 A369348 * A369350 A369351 A369352

Keyword

nonn

Author

Scott R. Shannon, Jan 21 2024

Status

approved