340 Jean-Marie De Koninck
1 478 674 861
the smallest prime number q such that

p≤q
p is divisible by
p≤23
p: here
this sum is equal to 53 064 863 142 321 030 (see the number 269).
1 479 604 544
the smallest number which can be written as the sum of four fifth powers in
three distinct ways: 1 479 604 544 =
35 +485 +525 +615
=
135 +365 +515 +645
=
185
+
365
+
445
+
665.
1 480 028 171
the prime number p located at the center of a 3 × 3 magic square made up
entirely of prime numbers (the other eight elements of this magic square being
p ± 12, p ± 18, p ± 30 and p ± 42) and discovered by H. Nelson (R.K. Guy [101],
A6).
1 533 776 805
the fourth number 1 which is both triangular and pentagonal:
1 533 776 805 =
55385 · 55386
2
=
31977(3 · 31977 1)
2
(see the number 210).
1 611 308 699
the smallest number n such that P (n)
6

n and P (n + 1)
6

n + 1: here
P (1611308699) = P
(74
· 11 ·
132
·
192)
= 19 34.23 6
ò
1611308699 and
P (1611308700) = P
(22
·
36
·
52
· 23 ·
312)
= 31 34.23 6

1611308700 (see the
number 2
400)201.
1 622 632 573
the 11th horse number (see the number 13).
1 631 432 881
the seventh number which is both a triangular number and a perfect square:
1 631 432 881 =
57121(57121+1)
2
=
403912
(see the number 36).
201One can prove that this sequence is infinite: see the footnote tied to the number 2 400.
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