A237131 Numbers k such that cos(k) = sin(d(1)*d(2)*...*d(q)) where d(1)d(2)...d(q) denotes the decimal expansion of k and the angles are in degrees.
90, 270, 375, 418, 450, 630, 726, 735, 778, 810, 990, 999, 1146, 1170, 1350, 1371, 1386, 1395, 1446, 1494, 1530, 1710, 1731, 1890, 1998, 2070, 2218, 2250, 2394, 2430, 2482, 2610, 2790, 2842, 2898, 2970, 3150, 3171, 3186, 3195, 3312, 3330, 3366, 3375, 3393
Offset: 1
Examples
2482 is in the sequence because cos(2482°) = sin(2*4*8*2°)= 0.7880107536067219... (A019861).
Crossrefs
Cf. A237129.
Programs
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Maple
with(numtheory):err:=1/10^10:Digits:=20:for n from 1 to 5000 do:x:=convert(n,base,10):n1:=nops(x):p:=product('x[i]', 'i'=1..n1):s1:=evalf(cos(n*Pi/180)):s2:=evalf(sin(p*Pi/180)):if abs(s1-s2)
Extensions
Name edited by Jon E. Schoenfield, Sep 12 2017